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Trends in Birth Rates, Sex Ratio, and Infant Mortality Rates Among Singletons, Twins, and Higher Order Multiples in Brazil Between 2010 and 2023

Published online by Cambridge University Press:  13 April 2026

Tania Kiehl Lucci ,
Bernardo Schonhorst de Oliveira ,
Claudia Monteiro Peixoto ,
Isabella Ribeiro Rodrigues ,
Claudio Possani ,
Ricardo Prist ,
Nancy L. Segal Open the ORCID record for Nancy L. Segal [Opens in a new window] ,
Edna Lúcia Tinoco Ponciano ,
Silvia Regina Dias Medici Saldiva  and
Mariana Azevedo Carvalho Open the ORCID record for Mariana Azevedo Carvalho [Opens in a new window]
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Tania Kiehl Lucci
Affiliation:
Departamento de Psicologia Experimental, Universidade de São Paulo, Brazil
Bernardo Schonhorst de Oliveira
Affiliation:
Instituto de Matemática e Estatística, Universidade de São Paulo, Brazil
Claudia Monteiro Peixoto
Affiliation:
Departamento de Matemática Aplicada, Universidade de São Paulo, Brazil
Isabella Ribeiro Rodrigues
Affiliation:
Departamento de Psicologia Experimental, Universidade de São Paulo, Brazil
Claudio Possani
Affiliation:
Instituto de Matemática e Estatística, Universidade de São Paulo, Brazil
Ricardo Prist
Affiliation:
Departamento de Psicologia Experimental, Universidade de São Paulo, Brazil
Nancy L. Segal
Affiliation:
Psychology, California State University Fullerton, USA
Edna Lúcia Tinoco Ponciano
Affiliation:
Instituto de Psicologia, Universidade do Estado do Rio de Janeiro, Brazil
Silvia Regina Dias Medici Saldiva
Affiliation:
Faculdade de Medicina, Universidade de São Paulo, Brazil
Mariana Azevedo Carvalho
Affiliation:
Departamento de Obstetricia e Ginecologia, Universidade de São Paulo Faculdade de Medicina, Brazil
Emma Otta*
Affiliation:
Departamento de Psicologia Experimental, Universidade de São Paulo, Brazil
*
Corresponding author: Emma Otta; Email: emmaotta@gmail.com
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Abstract

This study examines birth rates and infant mortality rates in Brazil among singletons, twins, and higher order multiples between 2010 and 2023. Data were obtained from the Brazilian Ministry of Health’s Live Birth Information System and Infant Mortality Information System. The dataset comprised 39,663,928 live births and 464,843 infant deaths occurring within the first year of life. Twin birth rates increased steadily over time, while singleton birth rates declined. The highest twin birth rates were observed in the Southeast (11.64‰) and South (11.47‰), whereas the lowest were observed in the North (7.81‰) and Northeast (9.23‰). Infant mortality among twins was approximately five times higher than among singleton, and higher order multiples faced an approximately threefold greater risk compared to singletons. Infant mortality rates were highest in the North and Northeast and lowest in the Southeast and South. Sex ratios varied by gestation type, with singletons showing the expected male bias and twins a slightly reduced male proportion, reflecting biological and regional influences on birth rates in Brazil. The data reveal a marked demographic shift between 2010 and 2023, with birth rates declining among women in their teens and 20s and increasing among those in their late 30s and 40s. Using Weinberg’s differential method, we identified divergent trends in zygosity: dizygotic birth rates increased significantly over time, whereas monozygotic rates remained stable. This contrast underscores the environmentally responsive nature of dizygotic twinning, particularly its association with advancing maternal age and assisted reproductive technologies, compared to the relatively biologically stable pattern of monozygotic twinning.

Keywords

Multiple birthsInfant mortalitySex ratio at birthRegional differencesBirth rates

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Twin Research and Human Genetics , First View , pp. 1 - 10
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© The Author(s), 2026. Published by Cambridge University Press on behalf of International Society for Twin Studies

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References

Agência Nacional de Vigilância Sanitária. (2024). 15º Relatório do Sistema Nacional de Produção de Embriões (SisEmbrio) [15th National Embryo Production System Report]. Ministério da Saúde. https://www.gov.br/anvisa/pt-br Google Scholar
Almeida, W. D. S. D., & Szwarcwald, C. L. (2012). Infant mortality and geographic access to childbirth in Brazilian municipalities. Revista de Saude Publica, 46, 68–76. https://doi.org/10.1590/s0034-89102012005000003 CrossRefGoogle ScholarPubMed
Beck, J. J., Bruins, S., Mbarek, H., Davies, G., & Boomsma, D. (2021). Biology and genetics of dizygotic and monozygotic twinning. In Khalil, A., Lewi, L., & Lopriore, E. (Eds.), Twins and higher-order pregnancies (pp. 31–50). Springer Nature. https://doi.org/10.1007/978-3-030-47652-6_3 CrossRefGoogle Scholar
Beemsterboer, S. N., Homburg, R., Gorter, N. A., Schats, R., Hompes, P. G., & Lambalk, C. B. (2006). The paradox of declining fertility but increasing twinning rates with advancing maternal age. Human Reproduction, 21, 1531–1532. https://doi.org/10.1093/humrep/del009 CrossRefGoogle ScholarPubMed
Buekens, P., MacGillivray, I., Campbell, D., Dramaix, M., Darquennes, H., Derom, R., & Thiery, M. (1991). Social differences in low birthweight and pre-term deliveries in twins. Paediatric and Perinatal Epidemiology, 5, 276–285. https://doi.org/10.1111/j.1365-3016.1992.tb00293.x CrossRefGoogle Scholar
Bulmer, M. G. (1970). The biology of twinning in man. Clarendon Press.Google Scholar
Cardoso-dos-Santos, A. C., Boquett, J., Oliveira, M. Z. D., Callegari-Jacques, S. M., Barbian, M. H., Sanseverino, M. T. V., Matte, U., & Schuler-Faccini, L. (2018). Twin peaks: A spatial and temporal study of twinning rates in Brazil. PloS One, 13, e0200885. https://doi.org/10.1371/journal.pone.0200885 CrossRefGoogle ScholarPubMed
Castro, M. C., Massuda, A., Almeida, G., Menezes-Filho, N. A., Andrade, M. V., de Souza Noronha, K. V. M., Rocha, R., Macinko, J., Hone, T., Tasca, R., Giovanella, L., Malik, A. M., Werneck, H., Fachini, L. A., & Atun, R. (2019). Brazil’s unified health system: The first 30 years and prospects for the future. The Lancet, 394, 345–356. https://doi.org/10.1016/S0140-6736(19)31243-7 CrossRefGoogle ScholarPubMed
Cooperstock, M., & Campbell, J. (1996). Excess males in pre-term birth: interactions with gestational age, race, and multiple birth. Obstetrics and Gynecology, 88, 189–193. https://doi.org/10.1016/0029-7844(96)00106-8 CrossRefGoogle Scholar
Cooperstock, M. S., Bakewell, J., Herman, A., & Schramm, W.F. (1998). Effects of fetal sex and race on risk of very pre-term birth in twins. American Journal of Obstetrics and Gynecology 179, 762–765. https://doi.org/10.1016/s0002-9378(98)70079-1 CrossRefGoogle Scholar
Colletto, G. M., Segre, C. A., Rielli, S. T., & Rosário, H. (2003). Multiple birth rates according to different socioeconomic levels: an analysis of four hospitals from the city of Sao Paulo, Brazil. Twin Research and Human Genetics, 6, 177–182. https://doi.org/10.1375/twin.6.3.177 CrossRefGoogle ScholarPubMed
Drevenstedt, G. L., Crimmins, E. M., Vasunilashorn, S., & Finch, C. E. (2008). The rise and fall of excess male infant mortality. Proceedings of the National academy of Sciences, 105, 5016–5021. https://doi.org/10.1073/pnas.0800221105 CrossRefGoogle ScholarPubMed
Fellman, J., & Eriksson, A. W. (2006). Weinberg’s differential rule reconsidered. Human Biology, 78, 253–275. https://doi.org/10.1353/hub.2006.0044 CrossRefGoogle ScholarPubMed
França, G. V., Restrepo-Méndez, M. C., Maia, M. F. S., Victora, C. G., & Barros, A. J. (2016). Coverage and equity in reproductive and maternal health interventions in Brazil: Impressive progress following the implementation of the Unified Health System. International Journal for Equity in Health, 15, 149. https://doi.org/10.1186/s12939-016-0445-2 CrossRefGoogle ScholarPubMed
Haghighi, L., Najmi, Z., Barzegar, S. H., & Barzegar, N. (2013). Twin’s sex and risk of pre-term birth. Journal of Obstetrics and Gynaecology, 33, 823–826. https://doi.org/10.3109/01443615.2013.831051 CrossRefGoogle ScholarPubMed
Hall, J. G. (2003). Twinning. The Lancet, 362, 735–743. https://doi.org/10.1016/S0140-6736(03)14237-7 CrossRefGoogle ScholarPubMed
Hoekstra, C., Zhao, Z. Z., Lambalk, C. B., Willemsen, G., Martin, N. G., Boomsma, D. I., & Montgomery, G. W. (2008). Dizygotic twinning. Human Reproduction Update, 14, 37–47. https://doi.org/10.1093/humupd/dmm036 CrossRefGoogle ScholarPubMed
James, W. H. (1975). Sex ratio in twin births. Annals of Human Biology, 2(4), 365–378. https://doi.org/10.1080/03014467500000981 CrossRefGoogle ScholarPubMed
Lee, D. S., & Barclay, K. J. (2025). More twins expected in low-income countries with later maternal ages at birth and population growth. Human Reproduction, 40, 372–381. https://doi.org/10.1093/humrep/deae276 CrossRefGoogle ScholarPubMed
Lee, G., Andrade, G. M., Kim, Y. J., & Anumba, D. O. (2025). The sex difference in the pathophysiology of preterm birth. Cells, 14, 1084. https://doi.org/10.3390/cells14141084 CrossRefGoogle ScholarPubMed
McCarthy, M. M. (2019). Stress during pregnancy: fetal males pay the price. Proceedings of the National Academy of Sciences U S A., 116, 23877–23879. https://doi.org/10.1073/pnas.1916909116 CrossRefGoogle ScholarPubMed
Monden, C., Pison, G., & Smits, J. (2021). Twin peaks: More twinning in humans than ever before. Human Reproduction, 36, 1666–1673. https://doi.org/10.1093/humrep/deab029 CrossRefGoogle Scholar
Murray, S., MacKay, D., Stock, S., Pell, J., & Norman, J. (2020). Association of gestational age at birth with risk of perinatal mortality and special educational need among twins. JAMA Pediatrics, 174, 437–445. https://doi.org/10.1001/jamapediatrics.2019.6317 CrossRefGoogle ScholarPubMed
Otta, E., Fernandes, E. D. S., Acquaviva, T. G., Lucci, T. K., Kiehl, L. C., Varella, M. A., Segal, N. L., & Valentova, J. V. (2016). Twinning and multiple birth rates according to maternal age in the city of São Paulo, Brazil: 2003–2014. Twin Research and Human Genetics, 19, 679–686. https://doi.org/10.1017/thg.2016.75 CrossRefGoogle Scholar
Otta, E., de Souza Fernandes, E., Bueno, J. A., Dos Santos, K. L., Segal, N. L., Lucci, T. K., Ferreira, I. F., Cesar, G. C., David, V. F., Tatit, D. P., Short, P. C. A., Fernandes, L. O., Crispim, A. C., Moretto, M. L. T., Andrade, N. C., Corte, S., Tobo, P. R., Barrichello, C. R., de Sousa, R. C. G., … Ribeiro, F. J. L. (2019). The University of São Paulo Twin Panel: Current status and prospects for Brazilian twin studies in behavioral research. Twin Research and Human Genetics, 22, 467–474. https://doi.org/10.1017/thg.2019.34 CrossRefGoogle Scholar
Pison, G., Monden, C., & Smits, J. (2015). Twinning rates in developed countries: trends and explanations. Population and Development Review, 41, 629–649. https://doi.org/10.1111/j.1728-4457.2015.00088.x CrossRefGoogle Scholar
Pongou, R. (2013). Why is infant mortality higher in boys than in girls? A new hypothesis based on preconception environment and evidence from a large sample of twins. Demography, 50, 421–444. https://doi.org/10.1007/s13524-012-0161-5 CrossRefGoogle Scholar
Reynolds, M. A., Schieve, L. A., Martin, J. A., Jeng, G., & Macaluso, M. (2003). Trends in multiple births conceived using assisted reproductive technology, United States, 1997–2000. Pediatrics, 111, 1159–1162. https://doi.org/10.1542/peds.111.S1.1159 CrossRefGoogle ScholarPubMed
Santana, D. S., Souza, R. T., Surita, F. G., Argenton, J. L., Silva, C. M., & Cecatti, J. G. (2018). Twin Pregnancy in Brazil: A profile analysis exploring population information from the National Birth E-Registry on live births. BioMed Research International, 2018, 9189648. https://doi.org/10.1155/2018/9189648 CrossRefGoogle Scholar
Smits, J., & Monden, C. (2011). Twinning across the developing world. PloS One, 6, e25239. https://doi.org/10.1371/journal.pone.0025239 CrossRefGoogle ScholarPubMed
Trivers, R. L., Willard, D. E. (1973). Natural selection of parental ability to vary the sex ratio of offspring. Science, 179, 90–92. https://doi.org/10.1126/science.179.4068.90 CrossRefGoogle ScholarPubMed
Varella, M., Fernandes, E., Arantes, J., Acquaviva, T., Lucci, T., Hsu, R., David, V., Bussab, V., Valentova, J., Segal, N., & Otta, E. (2019). Twinning as an evolved age-dependent physiological mechanism: Evidence from large Brazilian samples. In Elito, J. Jr (Ed.), Multiplepregnancies. New challenges. IntechOpen. https://www.intechopen.com/books/multiple-pregnancy-new-challenges Google Scholar
Victora, C. G., Barreto, M. L., do Carmo Leal, M., Monteiro, C. A., Schmidt, M. I., Paim, J., Bastos, F. I., Almeida, C., Bahia, L., Travassos, C., Reichenheim, M., Barros, F. C.; Lancet Brazil Series Working Group. (2011). Health conditions and health-policy innovations in Brazil: the way forward. The Lancet, 377, 2042–2053. https://doi.org/10.1016/S0140-6736(11)60055-X CrossRefGoogle ScholarPubMed
Voskamp, B. J., Peelen, M. J., Ravelli, A. C., van der Lee, R., Mol, B. W., Pajkrt, E., … & Kazemier, B. M. (2020). Association between fetal sex, birthweight percentile and adverse pregnancy outcome. Acta Obstetricia et Gynecologica Scandinavica, 99, 48–58. https://doi.org/10.1111/aogs.13709 CrossRefGoogle ScholarPubMed
Wells, J. C. (2000). Natural selection and sex differences in morbidity and mortality in early life. Journal of Theoretical Biology, 202, 65–76. https://doi.org/10.1006/jtbi.1999.1044 CrossRefGoogle ScholarPubMed
Wenstrom, K. D., & Gall, S. A. (1988). Incidence, morbidity and mortality, and diagnosis of twin gestations. Clinics in Perinatology, 15, 1–11. https://doi.org/10.1016/S0095-5108(18)30721-8 CrossRefGoogle ScholarPubMed