In their recent paper, Brannigan et al (Reference Brannigan, Tanskanen, Huttunen, Cannon, Leacy and Clarke2020) describe their examination of the relationship between self-reported maternal stress during pregnancy, and the subsequent development of personality disorder in the offspring. We would like to raise several points about the study and the conclusions drawn by the authors.

The study is based on the results of a subjective, single-item, three-point Likert scale completed at unspecified point(s) during pregnancy. Women were asked whether they had experienced ‘no stress’, ‘some stress’, or ‘notable stress’ since their last antenatal appointment. Of the entire cohort of 6468 women, 3626 completed the Likert scale questionnaire at least once during their pregnancy; these women were included in the analysis. A further 2842 women were not included in the analysis, presumably because they did not complete the questionnaire. We question whether this is a valid or meaningful measure of stress during the antenatal period.

A wide range of biological, psychological and social stressors may contribute to subjective feelings of stress. Perhaps it is the ongoing impact of these stressors, rather than prenatal maternal stress per se, that lead to the increased odds of a subsequent diagnosis of personality disorder. Furthermore, in many cases stress does not resolve immediately after giving birth: is it possible that ongoing maternal stress in the postnatal period (and beyond) might have a more significant impact on parenting practices, and thus on a child's development?

Maternal well-being and mental health is an important area of study, and the authors rightly note that there is a strong evidence base to support the use of interventions to reduce maternal stress. However, this paper implies a causal link between antenatal maternal stress and subsequent diagnosis of personality disorder that is not evidenced by the method and results presented here. We feel that research in this area should be reported carefully, to avoid contributing to a potentially harmful culture of mother-blaming.