A new study published in the BMJ has hinted at a possible link between some SSRIs (selective serotonin reuptake inhibitors) antidepressants and increased birth defect risks when taken during early pregnancy.
A team of researchers from the US and Canada combined results from independent published analyses with data from the US National Birth Defects Prevention Study (NBDPS) for their latest study that aimed to provide a more robust estimate of the association between individual SSRIs and birth defects.
Basing their analysis on 17,952 mothers of infants with birth defects and 9,857 mothers of infants without birth defects, born between 1997 and 2009, the researchers note that they have observed an association between previously reported birth defects and few SSRIs.
For the research, use of the SSRI drugs citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac), paroxetine (Paxil), or sertraline (Zoloft) at least once in the period from one month before conception through the third month of pregnancy was recorded. Researcher excluded those women who took antidepressants other than SSRIs or reported pre-existing diabetes.
Researcher reported that two previously reported birth defects associated with fluoxetine treatment were observed – heart wall defects and irregular skull shape (craniosynostosis). Five previously reported birth defects associated with paroxetine treatment were also seen – including heart defects, problems with brain and skull formation (anencephaly), and abdominal wall defects.
Their research however pointed out that none of the five previously reported associations between sertraline and birth defects were confirmed. This bit was reassuring as about 40 per cent of women reporting use of an SSRI in early pregnancy used sertraline.
Further, for nine other previously reported associations between maternal SSRI use and birth defects in infants, findings were also consistent with no association.
Researchers point out that while their findings are reassuring evidence for some SSRIs, there is evidence that that some birth defects occur more frequently among the infants of women treated with paroxetine or fluoxetine in early pregnancy.
They stress that though their analysis hints at the validity of associations that were observed previously, the increase in the absolute risks, if the associations are causal, is small.
For example the absolute risks in the children of women who are treated with paroxetine early in pregnancy would increase for anencephaly from 2 per 10,000 to 7 per 10,000, and for one of the heart defects from 10 per 10,000 to 24 per 10,000.
The authors stress that if these associations are causal, the absolute risks for these birth defects are still low, and they call for further studies “to enable women and their healthcare providers to make more informed decisions about treatment.”
The association between use of antidepressants, especially SSRIs, during pregnancy and birth defects in the infants has been the topic of much discussion in recent years. Studies have reached conflicting conclusions, leading to uncertainty around the safety of antidepressant use during pregnancy. A number of specific birth defects have been described in previous studies of women taking SSRIs, and these were analysed further in the current study.
“Continued scrutiny of the association between SSRIs and birth defects is warranted,” they say, “and additional studies of specific SSRI treatments during pregnancy are needed to enable women and their healthcare providers to make more informed decisions about treatment.”
“Meanwhile, the current analysis provides guidance to the safest treatment options during early pregnancy to minimize the risk of major birth defects, while providing adequate treatment of maternal depression,” they conclude.
