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Abortion and mental health: quantitative synthesis and analysis of research published 1995–2009

  • Priscilla K. Coleman (a1)



Given the methodological limitations of recently published qualitative reviews of abortion and mental health, a quantitative synthesis was deemed necessary to represent more accurately the published literature and to provide clarity to clinicians.


To measure the association between abortion and indicators of adverse mental health, with subgroup effects calculated based on comparison groups (no abortion, unintended pregnancy delivered, pregnancy delivered) and particular outcomes. A secondary objective was to calculate population-attributable risk (PAR) statistics for each outcome.


After the application of methodologically based selection criteria and extraction rules to minimise bias, the sample comprised 22 studies, 36 measures of effect and 877 181 participants (163 831 experienced an abortion). Random effects pooled odds ratios were computed using adjusted odds ratios from the original studies and PAR statistics were derived from the pooled odds ratios.


Women who had undergone an abortion experienced an 81% increased risk of mental health problems, and nearly 10% of the incidence of mental health problems was shown to be attributable to abortion. The strongest subgroup estimates of increased risk occurred when abortion was compared with term pregnancy and when the outcomes pertained to substance use and suicidal behaviour.


This review offers the largest quantitative estimate of mental health risks associated with abortion available in the world literature. Calling into question the conclusions from traditional reviews, the results revealed a moderate to highly increased risk of mental health problems after abortion. Consistent with the tenets of evidence-based medicine, this information should inform the delivery of abortion services.

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14 Major, B, Cozzarelli, C, Cooper, ML, Zubek, J, Richards, C, Wilhite, M, et al. Psychological responses of women after first trimester abortion. Arch Gen Psychiatry 2000; 57: 777–84.
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16 Miller, WB. An empirical study of the psychological antecedents and consequences of induced abortion. J Soc Issues 1992; 48: 6793.
17 Miller, WB, Pasta, DJ, Dean, CL. Testing a model of the psychological consequences of abortion. In The New Civil War: The Psychology, Culture, and Politics of Abortion (eds Beckman, LJ, Harvey, SM): pp. 235–67. American Psychological Association, 1998.
18 Reardon, DC, Coleman, PK. Relative treatment rates for sleep disorders following abortion and childbirth: a prospective record-based study. Sleep 2006; 29: 105–6.
19 Slade, P, Heke, S, Fletcher, J, Stewart, PA. Comparison of medical and surgical methods of termination of pregnancy: choice, psychological consequences, and satisfaction with care. Br J Obstet Gynaecol 1998; 105: 1288–95.
20 Coleman, PK, Coyle, CT, Shuping, M, Rue, VM. Induced abortion and anxiety, mood, and substance abuse disorders: isolating the effects of abortion in the National Comorbidity Survey. J Psychiatr Res 2009; 43: 770–6.
21 Dingle, K, Alati, R, Clavarino, A, Najman, JM, Williams, GM. Pregnancy loss and psychiatric disorders in young women: an Australian birth cohort study. Br J Psychiatry 2008; 193: 455–60.
22 Fergusson, DM, Horwood, LJ, Boden, JM. Abortion and mental health disorders: evidence from a 30-year longitudinal study. Br J Psychiatry 2008; 193: 444–51.
23 Fergusson, DM, Horwood, LJ, Ridder, EM. Abortion in young women and subsequent mental health. J Child Psychol Psychiatry 2006; 47: 1624.
24 Pedersen, W. Childbirth, abortion and subsequent substance use in young women: a population-based longitudinal study. Addiction 2007; 102: 1971–8.
25 Lipsey, MW. Identifying interesting variables and analysis opportunities. In The Handbook of Research Synthesis and Meta-Analysis, 2nd edn (eds Cooper, H, Hedges, LV, Valentine, JC): 147–58. Russell Sage Foundation, 2009.
26 Coleman, PK, Reardon, DC, Cougle, J. Substance use among pregnant women in the context of previous reproductive loss and desire for current pregnancy. Br J Health Psychol 2005; 10: 255–68.
27 Steinberg, JR, Russo, NF. Abortion and anxiety: what's the relationship? Soc Sci Med 2008; 67: 238–52.
28 Coleman, PK, Maxey, DC, Spence, M, Nixon, C. The choice to abort among mothers living under ecologically deprived conditions: predictors and consequences. Int J Ment Health Addiction 2009; 7: 405–22.
29 Coleman, PK, Reardon, DC, Rue, V, Cougle, J. History of induced abortion in relation to substance use during subsequent pregnancies carried to term. Am J Obstet Gynecol 2002; 187: 1673–8.
30 Coleman, PK, Reardon, DC, Rue, V, Cougle, J. State-funded abortions vs. deliveries: a comparison of outpatient mental health claims over four years. Am J Orthopsychiatry 2002; 72: 141–52.
31 Cougle, J, Reardon, DC, Coleman, PK. Depression associated with abortion and childbirth: a long-term analysis of the NLSY cohort. Med Sci Monit 2003; 9: CR105–12.
32 Cougle, J, Reardon, DC, Coleman, PK, Rue, VM. Generalized anxiety associated with unintended pregnancy: a cohort study of the 1995 National Survey of Family Growth. J Anxiety Disord 2005; 19: 137–42.
33 Gilchrist, AC, Hannaford, PC, Frank, P, Kay, CR. Termination of pregnancy and psychiatric morbidity. Br J Psychiatry 1995; 167: 243–8.
34 Gissler, M, Hemminki, E, Lonnqvist, J. Suicides after pregnancy in Finland, 1987–94: register linkage study. BMJ 1996; 313: 1431–4.
35 Pedersen, W. Abortion and depression: a population-based longitudinal study of young women. Scand J Public Health 2008; 36: 424–8.
36 Reardon, DC, Cougle, J. Depression and unintended pregnancy in the National Longitudinal Survey of Youth: a cohort study. BMJ 2002; 324: 151–2.
37 Reardon, DC, Cougle, J, Ney, PG, Scheuren, F, Coleman, PK, Strahan, TW. Deaths associated with delivery and abortion among California Medicaid patients: a record linkage study. South Med J 2002; 95: 834–41.
38 Reardon, DC, Cougle, J, Rue, VM, Shuping, M, Coleman, PK, Ney, PG. Psychiatric admissions of low-income women following abortion and childbirth. CMAJ 2003; 168: 1253–6.
39 Reardon, DC, Coleman, PK, Cougle, J. Substance use associated with prior history of abortion and unintended birth: a national cross sectional cohort study. Am J Drug Alcohol Abuse 2004; 26: 369–83.
40 Rees, DI, Sabia, JJ. The relationship between abortion and depression: new evidence from the Fragile Families and Child Wellbeing Study. Med Sci Monit 2007; 13: 430–6.
41 Schmiege, S, Russo, NF. Depression and unwanted first pregnancy: longitudinal cohort study. BMJ 2005; 331: 1303.
42 Taft, AJ, Watson, LF. Depression and termination of pregnancy (induced abortion) in a national cohort of young Australian women: the confounding effect of women's experience of violence. BMC Public Health 2008; 8: 75.
43 Borenstein, M, Hedges, LV, Higgins, JPT, Rothstein, HR. Introduction to Meta- Analysis. Wiley, 2009.
44 Appleby, L. Suicide during pregnancy and in the first postnatal year. BMJ 1991; 302: 137–40.
45 Kleiner, GJ, Greston, WM, (eds). Suicide in Pregnancy. John Wright, 1984.
46 Lindahl, V, Pearson, JL, Colpe, L. Prevalence of suicidality during pregnancy and the postpartum. Arch Womens Ment Health 2005; 8: 7787.
47 Schiff, MA, Grossman, DC. Adverse perinatal outcomes and risk of postpartum suicide attempt in Washington State, 1987–2001. Pediatrics 2006; 118: e66975.
48 Bailey, PE, Bruno, ZV, Bezerra, MF, Queiroz, J, Oliveira, CM, Chen-Mok, M. Adolescent pregnancy 1 year later: the effects of abortion vs. motherhood in Northeast Brazil. J Adolesc Health 2001; 29: 223–32.
49 Fergusson, DM, Boden, JM, Horwood, LJ. Abortion among young women and subsequent life outcomes. Perspect Sex Reprod Health 2007; 39: 612.
50 Fergusson, DM. Abortion and mental health. Psychiatr Bull 2008; 32: 321–4.
51 Mota, NP, Burnett, M, Sareen, J. Associations between abortion, mental disorders, and suicidal behaviour in a nationally representative sample. Can J Psychiatry 2010; 55: 239–47.

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Abortion and mental health: quantitative synthesis and analysis of research published 1995–2009

  • Priscilla K. Coleman (a1)


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Abortion and mental health: quantitative synthesis and analysis of research published 1995–2009

  • Priscilla K. Coleman (a1)
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Re:Abortion and mental health: quantitative synthesis and analysis of research published 1995-2009

Laura B. Page, High School Teacher
01 February 2012

I have followed with interest, both professional and personal, the commentary in this forum. The Coleman meta-analysis has been raked over the coals from multiple points of view, but I have yet to see any replication of the study with either concurrent or divergent results, nor any plans to attempt a similar study. On the contrary, most respondents have not been neutrally assessing the paper of a peer: they have angrily attacked a perceived threat.

My credentials, and thus my perspective, vary somewhat from most of those represented herein: I hold a B.A. in psychology, an M.B.A. in economics, and an M.Ed. in secondary education. I teach a variety of English, mathematics, and social science courses--including psychology--tohigh school and undergraduate students.

Working with young people daily, I inevitably learn their stories; pregnancy happens, and so does abortion. Many young women feel pressured into an abortion decision by boyfriend/husband, family, social, economic, or school circumstances. Add grief, guilt, and/or remorse to the mix, as well as the coping attempts (including risky behaviors) of the relatively immature, and the picture becomes increasingly complex. Granted, my evidence is purely anecdotal, but I have seen it: there is a connection between abortion and mental health, it needs to be studied further, and Coleman needs not to be the only one who researches it.

Those who have levied criticisms of Coleman's methodology might applytheir own criteria to her data, or gather their own data meeting her studycriteria, to prove or disprove her hypothesis. Others might start from scratch, formulate their own hypotheses, and proceed from there. Regardless, while I realize that the purpose of peer review is to open one's research to the criticism of other professionals, if all one does isto criticize, nothing has been achieved, and the goals of research have not been advanced. Worst of all, in this case, no women have been helped.

As to those concerned with bias, Coleman's follow-up comments are enlightening. Ultimately, valid results will emerge when multiple researchers, regardless of political persuasion, put their own biases aside, ask uncomfortable questions, and go where the data lead them.

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Conflict of interest: Page volunteers at a crisis pregnancy center, where she peer-counsels pregnant women and leads a support group for women who have had abortions in the past. Participation is voluntary and all services are offered free of charge. The center does not provide or refer for abortion services.

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Abortion, Mental Health and Charges of Guilt By Association

David C. Reardon, Director
17 January 2012

Coleman's meta-analysis of abortion and mental health studies was harshly criticized in three letters by five authors (Drs. Robinson, Stotland, Nadelson, Coyne, and Littell) who all cited an Ethics & Medicine(1) paper which I wrote (not Coleman) as evidence that Coleman cannot be trusted.

My full response(2) is summarized below:

Robinson's assertion that I am Coleman's "leader" is nonsense. We have no institutional, financial, or personal entanglements.

I gathered data that required the analysis of research psychologists. I am thankful that Coleman agreed to analyze it and help present it in a scientifically accurate and impartial manner.

As a biomedical ethicist, I explore the intersections of medicine, science, philosophy, theology, ethics, and the law. When writing papers intended for each of these fields, I seek to use the language and tools appropriate to each field.

The cited article was a response to a pro-life philosopher who argued that any evidence of emotional suffering of women following abortion is essentially irrelevant to the moral argument against abortion and counter productive to pro-life efforts.(3) The core of my response was that Christians have an obligation to "consistently demonstrate as much concern for women as for their unborn children," and that "our advocacy for women must be consistent and unconditional both for those who are facing crisis pregnancies and for those who have had abortions." I further argued that "the harm abortion does to women is just as real as that done to the human fetus."(1)

It also reflected my sincere belief that abortion involves substantial dangers to specific subgroups of women. Unfortunately critics have distorted this into the charge that I seek to scare women with exaggerated risks.(4) That is untrue. There are real risks, especially for certain higher risk groups.(5) Women should be told of the truth, with neither exaggeration nor dismissal and minimization.

Women who dare to express emotional trials following an abortion face rejection from people on both sides. A few pro-lifers harshly dismiss these women as "sinners" who deserve a lifetime of grief. Conversely, at least a few pro-choicers dismiss their grief as "whining," or "rare," or suggest that only women mentally unstable prior to their abortions would complain so much.(4)

By contrast, the post-abortion healing movement simply asks those on both sides to respect the experiences of women grieving a past abortion.

But even this pro-healing position is attacked. On one hand, pro-choicers accuse us of manipulating gullible women into falsely blaming unrelated life problems on their abortions.(4) Some pro-life advocates, meanwhile, accuse us of encouraging an unprincipled, narcissistic worldview that diminishes the moral absolutes regarding the sanctity of life.(3)

To my mind the question of whether abortion is the sole, direct cause of certain mental illnesses is far less important than the fact that many self-aware women believe it has contributed to their problems and are asking for understanding and help.(5) Why is it so hard to simply accept their self-assessments and stated needs? Women deserve better.


1. Reardon DC. A defense of the neglected rhetorical strategy (NRS) Ethics Med. 2002 Summer;18(2):23-32.

2. Reardon DC. Abortion and Mental Health Deniers' Attack and Distract Strategy. Oct. 22, 2011

3. Beckwith FJ. Taking abortion seriously: a philosophical critique of the new anti-abortion rhetorical shift. Ethics Med. 2001 Fall;17(3):155-66.

4. Baezlon E. Is There a Post-Abortion Syndrome? New York Times Magazine. January 21 2007

5. Burke T, Reardon DC. Forbidden Grief: The Unspoken Pain of Abortion. Springfield, Ill: Acorn Books; 2002.

CONFLICT OF INTEREST: I am the Director of the Elliot Institute
... More

Conflict of interest: None Declared

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The Correct Use of Ethics and Precaution with Regard to Abortion and Mental Health

Christian Munthe, Professor of Practical Philosophy
04 January 2012

The debate on Coleman's study has moved into ethics, as commentators claim it to support conclusions about the organisation of abortion services (AS). In her reply, Coleman sides with these voices. However, closer scrutiny puts these suggestion into question.

Koch argue that a "principle of precaution" (PP) supports the notion AS providing pre-counselling about possible risks to mental health,since PP says that merely possible risk may motivate preventive action. However, this holds for all risks, also those imposed by preventive actions. PP has to be allowed to thus "cut both ways" to avoid incoherenceand paradox [1, 2]. To appraise if some action, B, to prevent a possibly risky action, A, should be taken, also the outcomes of A and B, should there be no risk, needs consideration, as well as risks of B. If no causallink between abortion and mental helth exists, for AS to inform about a possible risk may scare away patients in spite of their reason to seek AS and may, moreover, impose risks on those choosing to have the procedure bydelaying it. Unbiased pre-counselling about the current scientific situation would not likely further patients' decision quality or avoid harm. It would have to work through the complexity of the current discussion, including the declared ideologic agenda of Coleman, bringing risks of confusing decision making and inducing harm. [3, 4]. Alternatively, quality-assured, manageable information offering a real chance of supporting decision making without inducing harm may be included. This expresses the idea of PP that potentially risky actions should be postponed waiting for clear evidence against too serious risks [2].

Puccetti argue that, regadless of Coleman's study, AS should include "in-depth analysis of the various factors known to interfere with the psychological outcomes" as a pre-procedure. The basis for this is thatabortion has not been shown to benefit mental health. No ethical principleis presented to back up this argument, but one may generalize the suggestion into one: If a health care practice has not been proven to be beneficial to mental health, it should not be allowed unless preceded by an in depth analysis of the various factors known to interfere with the psychological outcomes. This principle has far-reaching implications, since risk factors for mental health problems all across health care, while there is normally no proven mental health benefits. The principle also rules out the original suggestion: the suggested analysis should not be made before another analysis has been made and the same holds with respect to that additional analysis, and so on.

These proposals and Coleman's own response rest on the notion of the most important task being to discourage women from having abortions. If the ethical baseline is to be care for mental health, however, the proper conclusion should rather be about access to mental health care. If Colemanis wrong, anyone may be burdened by mental health problems independently of whetheher or not they contemplate abortion. If she is right, there should be a special readiness to attend to mental health needs in AS. If feasible, harmless pre-abortion identification of high-risk cases may be added to this. Neither Coleman nor her supporters have considered anythingin this vein and this adds to suspiscions of an undisclosed ideological conflicts of interest.

References1. Sandin P, Peterson M, Hansson SO, Rud?n C, Juthe A (2001). Five ChargesAgainst thePrecautionary Principle. Journal of Risk Research 5: 287-99.

2. Munthe C (2011). The Price of Precaution and the Ethics of Risk. Dordrecht, Heidelberg, London & New York: Springer, ch. 2.

3. Juth N (2005). Genetic Information: Values and Rights. Gothenburg:Acta Universitatis Gothoburgensis, ch. 3.

4. Juth N, Munthe C (2012). The Ethics of Screening in Health Care and Medicine. Dordrecht, Heidelberg, London & New York: Springer, ch. 4.

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Conflict of interest: CM has been conducting bioethics research and published blog-posts in the reproductive and related areas, often with results critical of typical so-called pro-life positions, but also arguing for regulation around medical and scientific practices.

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Re:Re: Abortion and Mental Health

Gregory L. Kinney, Epidemiologist
29 November 2011

An author should be commended for defending the work that they have done when that work is questioned by peers. Coleman however does not address a specific analytical observation made by authors that have commented (Coyne, Polis, Littel and Thygesen among others). Coleman included multiple analyses performed within multiple studies that represent the same study populations (Table 1, citation 10, 20, 21, 22, 24, 27, 29, 30, 32, 39 where each of these citations represents a study population being counted more than once in the meta-analysis). Doing so inappropriately increases the sample size and reduces the variance in the pooled measure. This causes the pooled estimate to be biased as the analytical technique was not applied in an appropriate manner and represents an inflated N. In her response the author addresses that observation by discussing random verses fixed effects and weighting but this is not the issue at hand;

"The random effects model yields an estimate of the mean of a distribution of true effects; whereas in the fixed effects model there is an assumption that all the included studies share one common effect. When assigning weights to studies in a fixed effects model, the smaller ones are afforded less importance, since the same effect is believed to be moreprecisely assessed in the larger studies. In contrast, in the random effects model, individual studies of varying sizes contribute data from distinct populations, all of which must be considered in the pooled estimate. Weighting is therefore more balanced in the random effects vs. fixed effects model with smaller studies given relatively more emphasis. In recognition of the heterogeneity, I not only employed the random effects model, but I ran separate meta-analyses based on distinct comparison groups and outcomes."

The author goes on to discuss her authorship of many of the included studies. This is done in the context of the existing literature and not the application of the specific analytical technique;

"Using the criteria outlined above, a significant proportion of the included studies (11/22) were articles that I authored or co- authored. However, having published 33 peer-reviewed articles, I believe I am more widely published on this topic than any other researcher in the world. It makes sense, therefore, that I am a co-author on a significant proportion of the included studies. Moreover, no studies satisfying the inclusion criteria were left out of the analyses."

Including ones own studies in a systematic review and meta-analysis is possible if done with care but that is, once again, not the issue at hand. The analytical issue is that the results of the meta-analyses reported in this study are incorrect because the meta-analysis was not performed in an appropriate manner and the independence assumption was violated. Authorship is not the issue; N is the issue.

Also Table 1 includes a citation inappropriately; Reardon & Cougle 2002 is cited as 35 which is actually Pederson 2008, Reardon & Cougle should be citation 36.

In light of the violation of a basic assumption of meta-analysis thispaper must be withdrawn. This violation biases the findings, their discussion and the conclusions and cannot be corrected in a response letter. This violation was pointed out by several other commenter's and the author failed to acknowledge and address it in her extensive response to comments.

... More

Conflict of interest: None declared

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Re: Abortion and Mental Health

Priscilla K. Coleman
17 November 2011

Dear Professor Tyrer:

I appreciate your decision to publish my meta-analysis on abortion and mental health in the British Journal of Psychiatry, despite the controversial results and critical commentary that has predictably followed. In the barrage of recent letters, the sentiments have varied widely and the many supportive arguments presented are worthy of additional comment; however, given space limitations, I have decided to focus on the criticisms to help ensure the results are given the attention deserved.

Before I address the most salient issues, I should note how encouraging it is to have a scholarly forum for discussing the many complexities inherent in conducting systematic reviews on this topic. The optimist in me is hopeful that this dialogue will foreshadow a new era wherein the research community is able to move beyond agendas and polarized discussions to focus exclusively on the well-being of women, the centre of this academic debate that is so frequently obscured.

There are some comments that I believe are without basis and may not have been made with a more careful, less emotional read of the article. For example, Littell and Coyne suggested scientific standards for systematic reviews were not followed. The protocol employed is detailed in the methodology section and the strategy was in line with recommendations in the Handbook of Research Synthesis and Meta-Analysis. Rather than focus on these types of comments, I address criticisms requiring more information from me to allow readers to make informed decisions regarding the merit of the issues raised. I specifically address heterogeneity, publication bias, selection criteria, and personal bias in the text that follows.

Heterogeneity: The studies included in the meta-analysis have a relatively high degree of heterogeneity given the demographic and cultural differences in sampling, the variability in control groups and outcomes, and differences in third variable controls, etc. Counter to the claim by Polis and colleagues, heterogeneity was addressed by employing a random effects model. The random effects model yields an estimate of the mean of a distribution of true effects; whereas in the fixed effects model there is an assumption that all the included studies share one common effect. When assigning weights to studies in a fixed effects model, the smaller ones are afforded less importance, since the same effect is believed to be more precisely assessed in the larger studies. In contrast, in the random effects model, individual studies of varying sizes contribute data from distinct populations, all of which must be considered in the pooled estimate. Weighting is therefore more balanced in the random effects vs. fixed effects model with smaller studies given relatively more emphasis.In recognition of the heterogeneity, I not only employed the random effects model, but I ran separate meta-analyses based on distinct comparison groups and outcomes.

Publication Bias: Goldacre and Lee provided a funnel plot analysis and presented it as evidence of publication bias. However, the funnel plot is largely inappropriate for heterogeneous meta-analyses, wherein studies are not likely from a single underlying population [1-4], and several investigatorshave warned that use of funnel plots with meta-analyses derived from heterogeneous samples may result in false-positive claims of publication bias [1-4]. When funnel plot asymmetry is detected in a heterogeneous meta-analysis, the cause is likely due to essential differences between the smaller and larger studies. For example, the majority of the smaller studies included in my meta-analysis employed substance use outcome variables and these outcomes tend to yield the strongest, most robust effects [5,6]. In addition, the larger studies were more likely than the smaller studies to include actual diagnoses for disorders, rarer events than cut off scores on single surveys. In the context of this meta-analysis, the funnel plot most certainly does not provide evidence of publication bias.

My experience attempting to locate unpublished data/studies on abortion and mental health has been very disheartening over the last 15 years,with virtually all requests ignored. I suspect reluctance to share unpublished data is an attempt to keep results that challenge contemporary views on abortion, indicating significant increased risks for adverse psychological effects,out of the public domain. In contrast, I believe energy is likely invested in seeing to it that non-significant findings, suggesting abortion carries no increased psychological risks, find their way into the journals. If there is any topic wherein many editors, researchers, and professional organizations are highly motivated to publish non-significant effects, it is this one, rendering publication bias less common than in other areas. Support for this notion can be found in the American Psychological Association's 42 year history of abortion advocacy.

In 1969 the APA passed a resolution which made the pro-choice political position the organization's official stance and declared abortion a civil right. For decades the APA has aligned itself with major organizations with pro-choice social agendas, including the American CivilLiberties Union Reproductive Freedom Project, National Abortion Federation, National Abortion Rights Action League, Guttmacher Institute, and Planned Parenthood among others, frequently submitting amicus briefs and providing congressional testimony. Martel[7] recently discussed the APA's position on abortion, among other issues,noting that the organization's stance has led them to promote psychological research and disseminate data to lawmakers to inform the public and advocate for societal change. Martel further pointed out that the political stance of theAPA lacks the strong backing of empirical data. With this long history of abortion advocacy by the strongest professional psychology organization in the world, politically motivated efforts to publish null findings to support and legitimize their position is logical.

Selection Criteria: As indicated under the methodology section of the meta-analysis, studies identified using the Medline and PsycINFO data bases were included based on sample size, comparison groups, outcome variables, controls for 3rd variables, use of odds ratios, and publication in English in peer-reviewed journals between 1995 and 2009. In an effort to isolate the effect of abortion on mental health, use of comparisons groups and controls for 3rd variables are basic methodological requirements consistent with the Bradford Hill criteria [8]. The majority of studies meeting these criteria and incorporated into the meta-analysis also had many other strong methodological features (multiple data points, nationally representative samples, etc.) I purposely avoided selecting from among the many more peripheral methodological criteria that could be argued as a necessary basis for including or excluding studies, when there is not universal agreement regarding strengths necessary to consider a study's results sufficiently reliable and valid, nor is there consensus on the particular deficiencies necessary for the wholesale dismissal of a study.

Using the criteria outlined above, a significant proportion of the included studies (11/22) were articles that I authored or co-authored. However, having published 33 peer-reviewed articles, I believe I am more widely published on this topic than any other researcher in the world. It makes sense, therefore, that I am a co-author on a significant proportion of the included studies. Moreover, no studies satisfying the inclusion criteria were left out of the analyses.

Curiously the issue of my not including a study by Danish researchers Munk-Olsen and colleagues published in the New England Journal of Medicine[9] was raised despite the fact that the paper came out long after my meta-analysis was completed and submitted for publication. Incidentally, the NEJM paper is presented as offering more reliable conclusions than the meta-analysis. However, there are several problematic features of this study. To begin with, Munk-Olsen and colleagues note that previous studies lack controls for third variables, but the only third variables they consider are age and parity. There are no controls for pregnancy intendedness, pressure to abort, marital status, income, education, exposure to violence and other traumas, etc. Many studies have been deemed inadequate based on only one of these variables not being accounted for (see APA Task Force Report [10]). The data indicated that rates of mental health problems were higher after abortion compared to childbirth (15.2% vs. 6.7%); however, the generally comparable rates before and after abortion were used to negate a possible causal link between abortion and mental health. This reasoning is problematic as many women were likely disturbed to the point of seeking help precisely because they were pregnant and contemplating an abortion or they were involved in troubled relationships. These factors may have resolved, yet disturbance rates remained elevated due to the impact of the abortion. Further, the Danish Civil Registration System contains over 40 years of data, but the researchers curiously compressed the study period to 12 years. A more appropriate strategy would have been to include all women experiencing an abortion, a birth, or no pregnancy and then compare pre and post-pregnancy mental health visits with statistical controls for all psychiatric visits pre-dating conception and all other relevant third variables described above.

Personal Bias: A quote from a presentation I gave at the annual meeting of the American Association of Prolife Obstetricians and Gynecologists was used by Goldacre and Lee to label me an "anti-abortion campaigner." This out of context comment was part of a broader call for more concerted efforts to create environments wherein objective scientists are able to make the psychology of abortion a priority. Once strong synopses of the best evidence are published, the data can and should be used to intelligibly inform policy. I am opposed to professional organizations like the APA creating a culture wherein it is perfectly acceptable for any political position (in this case pro-choice) to drive data collection efforts, restrict grants to researchers committed to a political agenda, serve as journal gatekeepers to block publication of findings that are not consonant with the political agenda, and ultimately use the biased information assembled to back policy.

I do not hold membership in any political organizations and my work has never been funded by any pro-life group. My expertise tends to be called upon by the pro-life community and unfortunately I am never asked to present my research or perspective on the literature to groups committed to a pro-choice political position. As a professor at a public university, what motivates me is simply the desire to foster high quality research and reach as many people as one individual can with an accurate appraisal of the literature, given the biases that permeate the study of abortion and dissemination of information through the usual channels. I do not have many graduate students working with me or large grants, and it is alarming that a researcher with such modest resources was the first to conduct a major quantitative review.

Rather than hurling unfounded accusations of personal bias, we need to more effectively utilize the well-established methods of science to fairly scrutinize the methodologies of individual studies, expand the empirical investigation of abortion and mental health, and develop a consensus-based standardized set of criteria for ranking studies meriting inclusion in reviews. Without agreement, the selected standards may be used to manipulate conclusions. For example, the ranking system employed by Charles et al. [11] ignored two central methodological considerations in prospective research designs: 1) percentage consenting toparticipate (no information was provided by the authors of the Gilchrist et al. [12] study that this team ranked as "Very Good"); and 2) retention of subjects over time. In the Gilchrist et al. study, only 34.4% of the termination group and 43.4% of the group that did not request termination were retained. A major problem with nearly all the recently published narrative reviews was somewhat arbitrary exclusion criteria at best and the purposeful selection of specific criteria resulting in dismissal of large bodies of evidence with politically incorrect results at worst.

By raising concerns of publication bias and attempting to undermine the credibility of an individual researcher, who managed to publish in a high profile journal, several people have sought to shift attention from the truly shameful and systemic bias that permeates the psychology of abortion. Professional organizations in the U.S. and elsewhere have arrogantly sought to distort the scientific literature and paternalistically deny women the information they deserve to make fully informed health care choices and receive necessary mental health counseling when and if an abortion decision proves detrimental.

1.Ioannidis JP, Trikalinos TA. The inappropriateness of asymmetry tests for publication bias in meta-analyses: a large survey. CMAJ l2007; 176 (3):1091-1096.

2.Lau J, Ioannidis JP, Terrin N, Schmid CH, Olkin I. The case of the misleading funnel plot. BMJ 2007; 333:597-600.

3.Terrin N, Schmid CH, Lau J, et al. Adjusting for publication bias in the presence of heterogeneity. Stat Med 2003;22:2113-26.

4.Ioannidis JP. Differentiating biases from genuine heterogeneity: distinguishing artifactual from substantive effects. In: Rothstein HR, Sutton AJ, Borenstein M, editors. Publication bias in meta-analysis: prevention, assessment and adjustments. Sussex: John Wiley and Sons; 2005. 287-302.

5.Coleman PK. Induced Abortion and increased risk of substance use: A review of the evidence. Current Women's Health Reviews 2005; 1: 21-34.

6.Mota NP, Burnett M, &Sareen J. Associations between abortion, mental disorders, and suicidal behaviour in a nationally representative sample. Can J Psychiatry 2010; 55(4):2 39-47.

7.Martel MM. The ethics of psychology's role in politics and the development and institution of social policy. Ethics & Behavior 2009; 19(2):103-111.

8.Hill BA. The environment and disease: Association or causation?Proceedings of the Royal Society of Medicine 1965; 58:295-300.

9.Munk-Olsen, T., et al., Induced first-trimester abortion and risk of mental disorder. N Engl J Med 2011; 364:332-9.

10.American Psychological Association Task Force on Mental Health and Abortion. Report of the American Psychological Association Task Force on Mental Health and Abortion 2008, Washington, DC: American Psychological Association.

11.Charles VE, Polis CB, Sridhara SK, Blum RW. Abortion and long-term mental health outcomes: a systematic review of the evidence. Contraception 2008;78:436-50.

12.Gilchrist A, Hannaford P, Frank P, Kay C. Termination of pregnancy and psychiatric morbidity. Br J Psychiatry 1995; 167:243-248.

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Conflict of interest: None declared

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Re: Abortion and Mental Health

Ben Goldacre, Wellcome Research Fellow in Epidemiology
07 November 2011

Professor Coleman's systematic review and meta-analysis of the literature on termination of pregnancy and mental health1 featured severalsignificant omissions: an undislosed conflict of interest; no assessment of publication bias; and no assessment of the quality of studies included.The search strategy was also inadequately reported, and the meta-analytic technique was faulty.

Firstly, the paper states "Declaration Of Interest: None". We believethis is incorrect. It seems that Professor Coleman is an anti-abortion campaigner, who has previously expressed the view that campaigning should include work in academic journals. For example, in a Powerpoint presentation on the website of the American Association of Pro-Life Obstetricians and Gynaecologists, Professor Coleman states:

"We need to develop organized research communities to continue theresearch, apply for grants, recruit young academics, critique dataproduced by pro-choice researchers, challenge politically biasedprofessional organizations, train experts to testify, and disseminatecohesive summaries of evidence."2

The British Journal of Psychiatry has committed to the International Committee of Medical Journal Editors uniform requirements for declaration of conflict of interest. This requires the declaration of "any relevant non-financial associations or interests (personal, professional, political, institutional, religious, or other) that a reasonable reader would want to know about in relation to the submitted work".3 As noted in a recent editorial, "the difficult words here are 'personal', ' relevant' and 'reasonable'."4 Given the role that campaigning has played around thisissue, we believe this conflict of interest should have been declared to readers.

Secondly, unusually for a systematic review and meta-analysis, there was no attempt to account for the role of publication bias in the findings. We have replicated the meta-analysis by importing Coleman's datainto Stata 11. After verifying that the summary odds ratios and confidenceintervals produced were identical, we went on to create a funnel plot (Figure 1) using metafunnel. This found evidence strongly suggestive of publication bias in the literature presented. We further used Egger's testusing the metabias command in Stata 11, and again found very strong evidence suggesting publication bias (p<0.0001).

"Figure 1. Funnel plot examining publication bias in data presented by Coleman 2011." [ATTACHED].

Thirdly, we are concerned to note that there was no attempt to account for quality of evidence, since a previous systematic review and meta-analysis found strong evidence for a relationship between methodological rigour and study results: "The highest quality studies had findings that were mostly neutral, suggesting few, if any, differences between women who had abortions and their respective comparison groups in terms of mental health sequelae. Conversely, studies with the most flawed methodology found negative mental health sequelae of abortion."5

Finally we note that there was only one assessor for the studies, andseveral of the included studies had more than one outcome, which were usedin the meta-analysis as if they were independent observations.

We believe that as a result of these features the paper falls far short of best practice in the execution of publication-standard meta-analyses.

Yours sincerely,

Ben Goldacre BA MA MSc MBBS MRCPsychWellcome Research Fellow in Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT.

William Lee BSc MBChB MRCPsych MSc Medical Research Council Training Fellow in Psychiatric Epidemiology, Institute of Psychiatry, De Crespigny Park, London SE5 8AF.


1. Coleman PK. Abortion and mental health: quantitative synthesis andanalysis of research published 1995-2009. The British Journal of Psychiatry. 2011;199(3):180-186. 2. Coleman PK. Powerpoint Presentation, American Association of Pro-Life Obstetricians and Gynaecologists. Available at: Accessed September 2, 2011. 3. ICMJE. Conflicts of Interest. Available at: Accessed September 2, 2011. 4. Tyrer P. From the Editor's desk. The British Journal of Psychiatry. 2009;196(1):86-86. 5. Charles VE, Polis CB, Sridhara SK, Blum RW. Abortion and long-term mental health outcomes: a systematic review of the evidence. Contraception. 2008;78(6):436-450.

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Conflict of interest: BG writes newspaper articles and books on problems in science, and has written three times previously about flaws in evidence used to campaign for changes in UK legislation to reduce access to termination of pregnancy, once online and twice in print, out of approximately 2,000 pieces published. Neither author is religious, neither has a history of engaging on the issue of termination of pregnancy beyond that mentioned here.

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Coleman Article Should be Retracted, Not Debated in a Subsequent Issue of BJP

James C Coyne, Professor
04 November 2011

Serious flaws in the reporting and conduct of the Coleman review should have been identified in pre-publication review and not left for readers of BJP to sort through subsequently. The article should be retracted and should not given the dignity of post-publication debate in asubsequent issue of the journal.

The review lacks the fundamental transparency that is expected of systematic reviews and meta-analyses and needed to allow readers to independently evaluate its conduct and interpretation of results without having first to go back to the original studies. Search strategies are noteven provided in sufficient detail for readers to ascertain the adequacy and completeness of the retrieval of relevant studies.

Results for 36 effects obtained from 22 studies that are integrated into a single effect size represent highly diverse outcomes ranging from smoking of marijuana to suicide. The overall effect size that is calculated does not generalize back to the individual outcomes in any meaningful way. This aspect of the meta-analysis recalls a photo often incorporated into workshops on meta-analysis. The photo depicts the famousroad sign for New Cuyama, California in which a total of 4663 is indicatedfor a population of 562, an elevation of 2150 feet, and a date of establishment of 1951. The calculation of an estimate of the heterogeneity of the effect size reported by Coleman is missing, in violation of standards for reporting a meta-analysis.

Multiple effects sizes are obtained from individual studies are integrated in a way that violates basic assumptions of independence of individual effect sizes that are required for a meaningful meta analysis. The 22 studies include 13 from Coleman's author group, and so the meta analysis violates usual expectations that a meta analysis be independent of the author group who generated the original studies. David Reardon who is a co-author of Coleman on a number of these studies has declared his strategy [1]:

"For the purpose of passing restrictive laws to protect women from unwanted and/or dangerous abortions, it does not matter if people have a pro-life view...In some cases, it is not even necessary to convince peopleof abortion's dangers. It is sufficient to simply raise enough doubts about abortion that they will refuse to actively oppose the proposed anti-abortion initiative. In other words, if we can convince many of those who do not see abortion to be a "serious moral evil" that they should support anti-abortion policies that protect women and reduce abortion rates, that is a sufficiently good end to justify NRS efforts. Converting these peopleto a pro-life view, where they respect life rather than simply fear abortion, is a second step. The latter is another good goal, but it is notnecessary to the accomplishment of other good goals, such as the passage of laws that protect women from dangerous abortions and thereby dramatically reduce abortion rates."

Many of the studies included in the Coleman meta-analysis, including most of the studies conducted by her group, are strongly criticized by other researchers and excluded from consideration in other systematic reviews, including a forthcoming report by the National Collaborating Centre for Mental Health (NCCMH) at the Royal College of Psychiatrists (RCPsych). One can only speculate on the timing of the BJP's publishing ofColeman's review relative to the impending release of the RCPsych report. Results of some of the original Coleman studies are not replicated in subsequent re-analyses of the same data sets by others.Coleman integrates results from studies without controlling for measures of mental health outcomes obtained prior to an abortion and in a number ofinstances, the mental health outcomes entered into her meta analysis were obtained before the abortion. In other instances, the effects reflect differences between women who obtained an abortion for an unwanted pregnancy versus women who delivered a wanted baby, a grossly inappropriate comparison if the intention is to obtain a valid estimate ofthe effects of abortion on mental health.

It is a mater of technical details, but important to evaluating Coleman's meta analysis that she used the wrong formula to calculate population-attributable risk and violated basic assumptions for such a calculation.

These serious flaws were apparent in a cursory reading of Coleman's article. I am confident that a closer read and a retrieval of the originalstudies and others that were ignored by Coleman would have yielded still more problems. But I think this analysis reaches the threshold for demonstrating the necessity of retracting the Coleman article and it begs an explanation for the nature of the peer review that led to the article being accepted.

The Coleman article is not a contribution to scientific literature but rather represents the revenge of Coleman and her offer group on the scientific community which has held their work to basic objective scientific standards, criticized its poor quality, and excluded from integration into systematic reviews on the basis of objective criteria.

1. Reardon DC (2002). A defense of the neglected rhetorical strategy (NRS). Ethics Med 18 (2): 23-32.

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Conflict of interest: None declared

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Coleman ignores established guidelines for proper scientific conduct of meta-analysis

Chelsea Polis, Associate
03 November 2011

Priscilla Coleman's recent meta-analysis [1] ignores guidelines for proper scientific conduct of meta-analyses of observational data. Her results violate at least three major principles of meta-analysis: (1) she fails to assess the underlying validity of included studies, (2) she failsto examine statistical heterogeneity, and (3) she illogically combines estimates for distinct outcomes. Furthermore, she accuses previous reviews of lacking "reasonable justification" for declining to quantitatively summarize effects, when declining to do so actually reflected sound epidemiologic judgment.

Coleman contends that "Through a process of systematically combining the quantitative results from numerous studies addressing the same basic question...far more reliable results are produced than from particular studies that are limited in size and scope." However, expert consensus suggests that "the likelihood that the treatment effect reported in a systematic review approximates the truth depends on the validity of the included studies..."[2] Coleman fails to assess the validity of included studies and erroneously asserts that "as a methodology wherein studies areweighted based on objective scientific criteria, meta-analysis offers a logical, more objective alternative to qualitative reviews..." In fact, studies in meta-analyses are typically weighted by sample size, which is not always related to study quality,[3] and decisions on which studies to include and how to include them remain subjective. If poor quality studies are included, as occurred in Coleman's review, a poor quality quantitative estimate will be generated. Coleman combines statistically heterogeneous results, and illogically combines effect estimates for outcomes that vary substantially (i.e., marijuana use and suicide); thus generating a summary estimate void of meaning or utility.

Meta-analysis of observational data can be useful when carefully conducted. However, it is essential that a summary estimate be accompanied by a qualitative description of risk of bias in included studies (which Coleman's review lacked) since "potential biases in the original studies, relative to biases in RCTs, make the calculation of a single summary estimate of effect of exposure potentially misleading."[4]

Coleman ignores other essential requirements of a high-quality statistical meta-analysis.[2] She makes no attempt to present a replicable search strategy or article selection diagram. She attempts to justify excluding articles prior to 1995 by noting that study methodology has improved, but fails to adequately justify selected cut-off dates. Ultimately, she includes multiple methodologically weak studies, and excludes at least two older but methodologically stronger studies. She authored her review alone, despite Cochrane and PRISMA recommendations to involve multiple reviewers to reduce the possibility of investigator bias or error.[2, 5]

Coleman makes disingenuous accusations about previous reviews. For example, she claims that our 2008 systematic review[6] "overlooked" ten articles which met inclusion criteria, and "lacked sufficient methodologically based selection criteria." This unfounded attack is puzzling, particularly since in 2008, we directly emailed to Coleman the reasons (consistent with our methodologically based selection criteria detailed on p. 437) for excluding seven of these ten articles. The remaining three (not previously inquired about) also fail to meet inclusion criteria: two had a follow-up period of less than 90 days and the other compared medical vs. surgical termination.

Coleman continues to ignore the scientific importance of accounting for pregnancy intention in this body of literature. If women who abort (many of which are unintended pregnancies) are compared against women who deliver (many of which are intended pregnancies), effects of unintended pregnancy are difficult to disentangle from effects of abortion. Circumstances surrounding an intentional versus an unintentional conception or pregnancy may be related to mental health outcomes. Most aborted pregnancies in the United States were unintended.[7] Coleman wrongly assumes that since nearly half of pregnancies in the US are unintended, most births are too, failing to acknowledge that almost half of unintended pregnancies end in abortion.[8] Thus, her assertion that "the majority of women in the control groups in studies comparing abortionwith term pregnancy actually delivered unintended pregnancies even if the variable was not directly assessed" has no empirical grounding. Similarly, her assertion that a "no pregnancy" group may be a "cleaner" comparison group ignores the fact that the "no pregnancy" group would not have experienced unintended pregnancy.

The scientific validity and rigor of Priscilla Coleman's work has been questioned before.[9] However, we are surprised and disappointed that the multiple egregious scientific errors in her review went undetected by the editorial or peer review process of the British Journal of Psychiatry.

Chelsea B. Polis, PhDAssociate, Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health

Vignetta E. Charles, PhDSenior Vice President, AIDS United

Robert Wm. Blum, MD, MPH, PhDWilliam H. Gates Sr. Professor and ChairDepartment of Population, Family and Reproductive Health, Johns Hopkins Bloomberg School of Public Health

Reference List

1. Coleman PK. Abortion and mental health: quantitative synthesis and analysis of research published 1995-2009. Br J Psychiatry 2011;199:180-186.

2. Liberati A, Altman DG, Tetzlaff J, Mulrow C, Gotzsche PC, Ioannidis JP, et al. The PRISMA statement for reporting systematic reviewsand meta-analyses of studies that evaluate health care interventions: explanation and elaboration. PLoS Med 2009;6:e1000100.

3. Egger M, Smith G, Schneider M. Systematic reviews of observational studies. In: Systematic reviews in health care: meta-analysis in context. Egger M, Smith G, Altman D (editors). London: BMJ Publishing Group; 2001. pp. 211-227.

4. Stroup DF, Berlin JA, Morton SC, Olkin I, Williamson GD, Rennie D, et al. Meta-analysis of observational studies in epidemiology: a proposal for reporting. Meta-analysis Of Observational Studies in Epidemiology (MOOSE) group. JAMA 2000;283:2008-2012.

5. Higgins J, Green S. Cochrane Handbook for Systematic Reviews of Interventions, Version 5.1.0. In: The Cochrane Collaboration; 2011.

6. Charles VE, Polis CB, Sridhara SK, Blum RW. Abortion and long-term mental health outcomes: a systematic review of the evidence. Contraception 2008;78:436-450.

7. Finer L, Henshaw S. Disparities in rates of unintended pregnancy in the United States, 1994 and 2001. Perspectives on Sexual and Reproductive Health 2006;38:90-95.

8. Finer L, Zolna M. Unintended pregnancy in the United States: incidence and disparities, 2006. Contraception 2011;in press.

9. Steinberg JR, Finer LB. Examining the association of abortion history and current mental health: A reanalysis of the National Comorbidity Survey using a common-risk-factors model. Soc Sci Med 2011;72:72-82.

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Conflict of interest: None declared

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The elusive problem of causation on the relationship between abortion and mental health problems. Does it really matter to avoid public health recommendations?

Elard S. Koch
02 November 2011

Elard Koch1, John Thorp2, Byron Calhoun3, Sergio Valenzuela4, Sebastian Gatica5, Juan M. Perez61Doctoral Program, Division of Epidemiology, School of Public Health, University of Chile; 2Department of Obstetrics and Gynecology, University of North Carolina-Chapel Hill, USA; 3Department of Obstetrics and Gynecology West Virginia University School of Medicine; 4Department of Bioethics, Faculty of Medicine University of Chile; 5Department of Family Medicine, Faculty of Medicine University of Chile; 6Department of Psychiatry, Faculty of Medicine, University of Chile.

The review and meta-analysis by P. K. Coleman offers the largest quantitative estimate of mental health risks associated with abortion available in the medical literature to date. This brings the question if there is or not a true causal relationship between abortion and psychological illness and if it is appropriate or not to make public health recommendations -i.e. by including this information to the abortion service- or in others words, if the evidence provided by Coleman's study justifies adopting what is currently defined in public health as the "principle of precaution" [1].Considering that abortion is a subject with strong politic, moral, philosophical and religious controversies, from a strictly scientific perspective and contrary to Coleman's study, previous qualitative reviews [2-4] have few or nothing to offer to solve the above mentioned questions. From an epidemiologic perspective, it also needs to be emphasized that Coleman applied a very strict inclusion criteria and extraction rules, no studies that met the criteria was left out, every study used a control group, had some controls for potential confounders such as socioeconomic factors, demographics, exposure to violence, and 12 out of the 22 studies included in the meta-analysis controlled for prior psychological history. In addition, the effects entered into the meta-analyses were adjusted odds ratios allowing the population-attributable risk to be computed. The approach used by the author allows avoiding any biased interpretation by purely subjective considerations. Previous letters by Howard et al., Robinson et al. y Lagro-Janssen et al. submitted immediately after the publication (see below) do not seem to even understand what Coleman really did or at least they are underestimating the rigorous methodology applied by the author, quoting substantially weaker studies or basing on the single study by Munk-Olsen et al. [5] - published after the submission of Coleman's study to the British Journal of Psychiatry - to dismiss any evidence suggesting that abortion may have adverse effects on mental health.CausationCausation is a complex issue, which has been largely discussed in epidemiology [6]. In deterministic models, like in most of the infectious diseases, infectious agents are a necessary and sufficient cause to generate the disease. However, not every infectious disease follows this deterministic model. For example, like in cervical cancer, human papillomavirus (HPV) is a necessary - yet not sufficient - cause of cancer: while HPV presence is confirmed in almost the totality of the cases, only a little fraction of them actually develop the cancer [7]. In non-transmissible chronic diseases the problem is even more complex. Most of chronic diseases cannot be granted a single cause, they are the result of multiple causes, being most of them neither necessary nor sufficient to generate the disease. Smoking habit is widely recognized to be one of the multiple causal factors to coronary heart disease and lung cancer, for example, but it is obvious that both diseases are also produced in non-smoking people too. Smoking is considered to be a component cause in a constellation of causal factors [6], which if present, increases the "risk" of a certain disease, regarding the non-smoking people. By logical synthesis in popperian models [8], smoking is therefore considered as "cause" of coronary heart disease and lung cancer. By applying this reasoning to the findings described by Coleman, abortion is neither a necessary nor sufficient cause to the mental health outcomes previously investigated, but it is possible to accept that it acts as a component cause of the above mentioned health problems.The problem of causation is an especially complex issue in psychiatry. The mental health problems analyzed in Coleman's review are not only multifactorial by nature, but these psychiatric entities are not themselves indivisible. Gnoseological entities such as anxiety, depression or suicidal behaviour can be understood as a cumulus of different pathological situations susceptible of classification into some of those categories; they are not well delimitated clinical entities and most of them habitually are recognized as "illness" instead of "disease" [9]. At this point, where exposure (abortion) is clearly defined, the mental outcome is not immediately clear and will depend on how it has been defined and evaluated in each one of the studies included in the meta-analysis. However, from an epidemiological perspective, it corresponds to analyze if it is plausible that the established association can be causal. A risk factor is not the same as a causal factor. While the first is an statistical association that rises after the direct comparison of the incidence rate of the disease event in an exposed population compared to another which is not exposed -i.e. the control population- the latter is a wider concept, having to satisfy a series of criteria not limited to statistical association and requiring of a plausible mechanistic explanation.Table. Hill's criteria for assessing a possible causal relationship between abortion and metal health Causal Criteria Accomplishment Strength Temporal Relationship The relationship has been established by longitudinal prospective designs. From 22 studies included in Coleman's meta-analysis, 6 were prospective, 7 case-control, and 9 cross-sectional.. + + - Strength (association) Refers to whether the associations (e.g. magnitudes of Odds Ratios) between abortion and various mental health problems are slight, moderate, or strong. Considering all outcomes, the association is slight to moderate. + + - Dose-Response Increasing the severity of the outcome, association is stronger. However, evidence of a dose response gradient with the number of abortions is not direct. + - - Consistency Refers to external validity and reproducibility. The number of reports from different populations showed consistency. Comparatively, few studies have reported negative results. Some of these studies only report a negative association after over-adjust by highly collinear variables such as previous antecedents of psychological illness. + + + Plausibility Studies suggest that abortion is a painful experience with ambivalent and contradictory feelings. Almost one-half also had parallel feelings of guilt, as they regarded abortion as a violation of their ethical values [10-11]. Thus, long term effects on mental health are plausible. + + - Alternate Explanations All the studies considered some controls for potential confounders such as socioeconomic factors, demographics, and exposure to domestic violence and 12 out of the 22 studies controlled for prior psychological history. + + - Experimental Evidence No direct experimental evidence exists currently in humans or animal models. - - - Specificity Although the exposure is well defined the mental outcomes assessed in the different studies are not unambiguous gnoseological entities. + - - Coherence Refers to internal validity and logical consistency. The sample consisted of 22 peer-reviewed studies (15 from the USA and 7 from other countries) and a total of 877,181 participants, of whom 163,831 had experienced an abortion. All the studies used a control non-exposed group including unintended pregnancy. + + + To actually accept that any epidemiological association is or is not causal, it is frequent to apply a group of causal criteria. Bradford Hill's criteria are the most widely accepted to evaluate inferences coming from observational epidemiologic studies [12]. In the table above we have applied these criteria to Coleman's study and we have classified the strength of each criteria with a qualitative scale (- - -; + - -; + + -; + + +). With the exception of experimental evidence, which for obvious reasons is really hard to obtain, the findings by Coleman seem to fit with different strength in these criteria. Therefore, it is necessary to accept that we may not just be in presence of an increased risk of different mental outcomes, but also in presence of a true cause-effect relationship between abortion and mental health problems. On the other hand, considering that, in logical terms, no epidemiologic study offers more than what its design contains [8], it is necessary to also accept that Coleman's meta-analysis does not solve the problems related to the inherent inaccuracy in the evaluated outcomes, the limitations of the included studies and the absence of a mechanistic explanation per se. Thus, causation is under considerable uncertainty and remains as a conjecture subjected to scientific undetermination.PrecautionConsidering the precaution principle, the burden of proof shifts from demonstrating the presence of risk to demonstrating its absence [13-15]. Thus, public health interventions for reducing the potential risks of exposure to potentially hazardous sources should be implemented until the hypothesis is definitively proven to be false [1]. According Douglas Weed [13] the process of public-health decision-making is often based on imperfect and uncertain evidence. Thus, the challenge is to find the level of evidence that provides an appropriate balance between what we know and our desire to benefit others. If science is not able to provide evidence of effects (or lack thereof), the adoption of public-health measures, such as the precaution principle, will solely depend on the contingent political sensitivity [1] based on social, religious, cultural, ideological or political agenda, such as individual rights and liberties or purely economic considerations, which may be obstacles to the implementation of evidence-based interventions [13-15] such as anti-smoking or anti-HIV campaigns. Although is desirable to implement an intervention when there is strong evidence of a causal relationship between exposure to a given factor and a disease event, causation in not a sine qua non requisite to do public health recommendations, specially, when these recommendations potentially benefit the population at risk. Moreover, without any evidence or justifiable reasons to suspect that the proposed intervention can have any deleterious consequence on health, to delay the implementation of a supposedly benefit public health intervention is potentially harmful.The public health recommendation after the study by Coleman is very simple: because abortion can be associated with an increased risk of mental health problems, women seeking abortion services should be informed about this greater risk. While it is unlikely that this simple recommendation have an immediate or relevant impact on the abortion incidence rate, the focus of our concern should be if this information can bring any benefit to the target population. If we consider that such warning can orientate women who have experienced abortion towards the seek of proper help in case of mental heath problems, then this recommendation, supported by the results of Coleman's meta-analysis, is completely justified, not being a direct matter if the causal relationship has been or not completely established or their mechanisms explained. In other words, because risk does not necessarily mean causation and the recommendation by P. K. Coleman is not directly related with the existence of a direct causal relationship, but with a consistent and robust estimation of an increased probability of some mental problems after abortion, we consider that women seeking abortion services merit to be informed about these findings. Opponents to this simple public health recommendation need to provide some evidence or valid arguments about any deleterious effect of informing women on the increased risk for mental health problems related to abortion; otherwise, it is not justified to delay its implementation.

REFERENCES Rezza G. The principle of precaution-based prevention: a Popperian paradox? Eur J Public Health 2006;16:576-7 American Psychological Association Task Force on Mental Health and Abortion. Report of the American Psychological Association Task Force on Mental Health and Abortion. APA, 2008. Charles VE, Polis CB, Sridhara SK, Blum RW. Abortion and long-term mental health outcomes: a systematic review of the evidence. Contraception 2008;78:436-50. Robinson GE, Stotland NL, Russo NF, Lang JA, Occhiogrosso M. Is there an 'abortion trauma syndrome'? Critiquing the evidence. Harv Rev Psychiatry 2009; 17:268-90. Munk-Olsen, T., et al., Induced first-trimester abortion and risk of mental disorder. N Engl J Med 2011;364:332-9. Rothman KJ, Greenland S. Causation and causal inference in epidemiology. Am J Public Health. 2005;95 Suppl 1:S144-50. Grce M, Davies P. Human papillomavirus testing for primary cervical cancer screening. Expert Rev Mol Diagn 2008;8:599-605. Koch E, Otarola A, Kirschbaum A. A landmark for popperian epidemiology: refutation of the randomised Aldactone evaluation study. J Epidemiol Community Health 2005;59:1000-6. Hofmann B. On the Triad Disease, Illness and Sickness. Journal of Medicine and Philosophy 2002;27(6):651-673. Ward AC. The role of causal criteria in causal inferences: Bradford Hill's "aspects of association". Epidemiol Perspect Innov 2009;17;6:2. Kero A, Hogberg U, Jacobsson L, Lalos A. Legal abortion: a painful necessity. Soc Sci Med 2001;53:1481-90. Kero A, Lalos A. Ambivalence--a logical response to legal abortion: a prospective study among women and men. J Psychosom Obstet Gynaecol 2000;21:81-91. Grandjean P, Bailar JC, Gee D, et al. Implications of the precautionary principle in research and policy-making. Am J Ind Med 2004;45:382-5. Weed DL. Precaution, prevention, and public health ethics. J Med Phyl 2004;29:313-32. Vineis P. Scientific basis for the precautionary principle. Toxicol Appl Pharmacol 2005;207:S658-S662.
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Conflict of interest: None declared

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Abortion and mental consequences: a further reading.

Renzo Puccetti, Medical doctor
02 November 2011

Sir, the study by Coleman (1) and the following comments may offer a further useful point of view also to the bioethical debate. Irrespectivelyof moral judgement, in the majority of cases abortion is performed by physicians to protect women's mental health from an unintended/unwanted pregnancy or birth but as a minimum what we can say is that evidence do not support any beneficial effect on their mental health derived from abortion. On the public health level abortion may therefore be considered no more than a procedure satisfying criteria for futility (2)(3). On the individual level any abortive procedure should be instead preceded by an in depth analysis of the various factors known to interfere with the psychological outcomes. But as far as we know this is almost never the case. If women's health is what abortion providers intend to preserve theyshould accept a substantial revision of their protocols under the assistance of skilled psychiatrists.

References:1. Coleman PK. Abortion and mental health: quantitative synthesis and analysis of research published 1995-2009. Br J Psychiatry. 2011 Sep;199:180-6. 2. Schneiderman LJ, Jecker NS, Jonsen AR. Medical futility: its meaning and ethical implications. Annals of Internal Medicine 1990 Jun;112:949-54.3. Waisel DB, Truog RD. The cardiopulmonary resuscitation-not-indicated order: futility revisited. Ann Intern Med. 1995 Feb;122(4):304-8.

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