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SSRI use during pregnancy is associated with fetal abnormalities

BMJ 2006; 333 doi: https://doi.org/10.1136/bmj.333.7573.824-d (Published 19 October 2006) Cite this as: BMJ 2006;333:824
  1. Roger Dobson
  1. Abergavenny

    Women who take selective serotonin reuptake inhibitors (SSRIs) during early pregnancy may increase the risk of having a child with a congenital malformation, a new study reports. However, the researchers say that it is not clear whether the increased risk is due to the drugs themselves or to other factors related to the women's underlying disease.

    The research, which was published online ahead of print publication in Epidemiology on 4 October, showed that women who took an SSRI during the second or third month of pregnancy had nearly twice the risk of having children with congenital malformations as women who took no SSRI during pregnancy (www.epidem.com, doi: 10.1097/01.ede.0000239581.76793.ae).

    No increased risk was found among women who used other types of antidepressants or among women who were prescribed SSRIs in late pregnancy.

    “Our data indicate a moderately increased risk of congenital malformations associated with prenatal exposure to SSRIs,” write the authors, from Aarhus University Hospital in Denmark. “Further studies are needed to confirm this risk and to clarify whether the risk is attributable to the drugs themselves, to underlying psychiatric disease, or to other confounding factors.”

    They say that the safety of taking SSRIs during pregnancy is an important public health concern but that data on teratogenicity in humans is limited because of small sample sizes.

    Among 151 831 women who had a live birth or stillbirth during the study period, 1051 women (0.7%) redeemed a prescription for an SSRI in early pregnancy (the authors included the period from 30 days before conception until the end of the first trimester). Of these, 453 women (0.3%) redeemed their prescription during the second or third month of pregnancy.

    The results showed that the 150 780 women with no SSRI prescription gave birth to 5112 children with congenital malformations (3.4%). The 1051 women who redeemed a prescription for an SSRI any time during early pregnancy gave birth to 51 children with congenital malformations (4.9%) (adjusted relative risk 1.34 (95% confidence interval 1 to 1.79)). The 453 women who redeemed a prescription for an SSRI during the second or third month of pregnancy gave birth to 31 children with congenital malformations (6.8%) (adjusted relative risk 1.84 (1.25 to 2.71)).

    Most of the malformations among the children of women who redeemed an SSRI prescription in early pregnancy were cardiovascular (29%), muscle and bone (31%), or digestive (14%) malformations.

    The authors say it is unclear whether the effects were caused by the SSRIs or were due to factors related to the underlying disease. They say that no evidence was shown that the association was specific to any particular malformation that may point to serotonin itself having some kind of effect.

    “The nonspecific increase in risks in our study could support a theory of generalised serotonin-mediated effect on malformations,” they wrote. “The specific SSRIs do not share chemical structures, and it has been speculated that any teratogenicity may be explained by serotonin-mediated effects on the embryonic development.”

    View Abstract