Antidepressants in pregnancy: Paroxetine in first trimester increases risk of birth defects

The use of the antidepressant paroxetine during the first 12 weeks of pregnancy can increase the risk of birth defects, researchers have said. A review of studies published between 1966 and November 2015 showed a 23% increase of major congenital malformations and a 28% increased risk of major cardiac malformations among newborns.

Antenatal depression is common – while statistics vary as to how many women suffer, it is thought around one in 10 will experience depression at some point during their pregnancy. The NHS notes that antidepressants are not normally recommended for pregnant women, but exceptions can be made if the risk posed by depression outweigh risks of treatment – if they are recommended, it is normally a type of antidepressant called selective serotonin reuptake inhibitor (SSRI).

In the latest study, which has been accepted for publication in the British Journal of Clinical Pharmacology, researchers note until 2005, paroxetine – an SSRI – was considered safe for use during pregnancy. While a small unpublished study by the drug manufacturer showed the potential for increased risk of cardiac malformations, subsequent research produced conflicting results.

To assess the risk of paroxetine, the University of Montreal team looked at 23 studies into the drug over 50 years. Their findings showed that compared to no use of paroxetine during the first trimester, risk of both cardiac and congenital malformations was increased. Normally the risk for cardiac malformations is 1%, with major malformations being 3%.

Concluding, the researchers said paroxetine "bears more risks than benefits" for pregnant women. Study leader Anick Bérard added: "Given that the benefits of antidepressants overall, and selective serotonin reuptake inhibitors including paroxetine specifically, during pregnancy is questionable at best, any increase in risk – small or large – is too high.

"Indeed, the risk/benefit ratio suggests non-use in women with mild to moderately depressive symptoms, which is 85% of pregnant women with depressive symptoms. Therefore, planning of pregnancy is essential, and valid treatment options such as psychotherapy or exercise regimens are warranted in this special population."