A multicenter study of women who used selective reuptake inhibitors (SSRIs) around the time they conceived shows an association with birth defects—but that the risks are not the same for all drugs in that class. Published in BMJ, the findings offer reassurance about some SSRIs while pointing to a need for caution in use of paroxetine or fluoxetine early in pregnancy.
Nearly 18,000 mothers of infants with and nearly 10,000 mothers of infants without birth defects were included in the Bayesian analysis, which was designed to look at associations between 14 categories of birth defects and SSRIs that had previously been reported in the literature. The data were from the US National Birth Defects Prevention Study, a case-control study of birth defects. The deliveries occurred in 10 different states and spanned 1997 to 2009 and the women were asked specifically about their use of SSRIs from 3 months before conception to the birth of their babies.
Among the women who bore infants with birth defects, 659 had been exposed to citalopram, escitalopram, fluoxetine, paroxetine, or sertraline during pregnancy, versus 298 in the control group. Sertraline was the most commonly used SSRI; about 40% of women in the control group reported using it.
The researchers’ findings showed no support for previous reports of an association between maternal SSRI use and 9 selected birth defects. None of the five previously reported associations between sertraline and birth defects were confirmed. However, high odds ratios were found for five birth defects with paroxetine (anencephaly 3.2, 95% credible interval 1.63-6.2; atrial septal defects 1.8, 1.1-3.0; right ventricular outflow tract obstruction defects 2.3, 1.4-3.9; gastroschisis 2.5, 1.2-4.8; and omphalocele 3.5, 1.3-8.0) and for two defects with fluoxetine (right ventricular outflow tract obstruction defects 2.0, 1.4-3.1 and craniosynostosis 1.9, 1.1-3.0).
The analysis, the authors said, “confirms the need to assess the association between specific SSRIs and specific birth defects rather than combining an entire drug class or heterogeneous group of birth defects.” While the data on use of SSRIs were self-reported by the mothers, the researchers consider it a strength of the study that the information reflected use of medications and not just prescriptions that were filled. They believe that their analysis offers a major advantage over previous reports in that individual SSRIs and birth defects were assessed, while accounting for earlier reported associations.