In the study, published in the British Medical Journal, researchers wanted to see if the birth defect risk affected the entire class of anti-depressant drugs known as SSRIs (selective serotonin reuptake inhibitors), or only select anti-depressants.
The link between the use of anti-depressants during pregnancy and birth defects in the infants has been a highly debated topic in recent years. Studies have reached conflicting conclusions, leading to uncertainty around the safety of anti-depressant use during pregnancy.
Previous studies found that specific birth defects have been detected in babies whose mothers took SSRIs. This prompted the U.S. Food and Drug Administration in 2005 to issue a safety warning about use of SSRIs during pregnancy. The aim of the current study was to find if all SSRIs were linked to birth defects.
The study looked at 27,809 women. The participants included 17,952 mothers of infants with birth defects and 9,857 mothers of infants without birth defects, born between 1997 and 2009.
The researchers asked the women whether they took any of the drugs – citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac), paroxetine (Paxil), or sertraline (Zoloft) – at least once in the one month before conception until the end of the first trimester.
They found that in women who took Prozac and Paxil early in pregnancy, birth defects occurred two to three-point-five times more frequently than in women who did not take them. The other anti-depressants in the study – Celexa, Lexapro or Zoloft – showed no effects.
In the women who took Prozac, two previously reported birth defects associated with fluoxetine treatment were observed – heart wall defects and irregular skull shape (craniosynostosis).
And in the women who toon Praxil, five previously reported birth defects associated with paroxetine treatment were seen. These included heart defects, problems with brain and skull formation (anencephaly), and abdominal wall defects.
The study’s authors noted that the risks appeared to be small. For example, in women who took paroxetine early in pregnancy, the risk for anencephaly rose from two cases per 10,000 to seven per 10,000. The risk for heart defects rose from 10 per 10,000 to 24 per 10,000.
The results in women taking Zoloft is reassuring since drug was used by some 40 percent of the women in the study and is not lined to any birth defect.
Researchers note the analysis was only able to show a link between the drugs and birth defects, but could not prove that the drugs caused the deformities.