Motherisk Newsletters: Spring 2003, No. 17

A Motherisk study, published in the March 2003 issue of the scientific journal The Canadian Journal of Psychiatry, demonstrates that the use of trazodone and nefazodone does not increase the rates of major malformations, above the expected baseline rate of one to three per cent.

This is the first study to evaluate the safety of these drugs during pregnancy. The researchers were able to ascertain the outcomes of 147 pregnancies after exposure to trazodone or nefazodone from women in five different geographical centres. All of the women used the drugs during the first trimester, with 35 per cent taking them throughout their pregnancies.

Of the 147 pregnancies followed, there were 121 live births, 20 spontaneous abortions, and 6 therapeutic abortions. The group was compared to two control groups (one group was on other non-teratogenic antidepressants and the second group was exposed to other non-teratogenic drugs). Among the three groups, pregnancy outcomes did not differ except that there were more spontaneous abortions in both antidepressant groups. These findings may indicate that women with depression suffer more miscarriages and should be researched further.

"These study results empower health professionals to assist their pregnant patients in making informed decisions about antidepressant use during pregnancy," says Adrienne Einarson, the study's lead author and assistant director of the Motherisk Program. "Increasing evidence-based information should reassure women and their health professionals that the benefits of taking an antidepressant in pregnancy can largely outweigh any unproven risks."