A study published in the Canadian Medical Association Journal this week has uncovered new evidence that women who take SSRIs (a popular class of antidepressants) during the first trimester may have an increased risk of miscarriage.
In the case-controlled study, researchers examined the records of 5,124 women who had a miscarriage, then randomly selected records from women who had carried a normal pregnancy. Statistical analyses on the sets of records uncovered that a greater percentage of the women who had miscarried were using antidepressants, and the use of antidepressants appeared to be associated with an increased risk of miscarriage that was independent of the reason for the prescription (meaning that the association appeared to be due to the drugs and not the depression itself). The risk seemed to be highest in women using more than one class of antidepressants and in women using paroxetene and venlaxafine.
In the past, some smaller studies had hinted that the drugs may not be entirely safe during pregnancy, but results had been contradictory with some studies but not others finding a link. This latest study used a larger sample size and performed more controlled analyses, which makes the results somewhat "more robust" (as described by a researcher quoted in a Business Week article about the study).
Nevertheless, many experts are urging caution in interpreting the results, pointing out that the results indicated women on antidepressants were 1.68 times more likely to miscarry -- less than twice as likely -- and that the benefits of antidepressants might outweigh the risks.
My own take on it would be that if this study is as "robust" as it sounds (the full text is available here), I hope this information is openly shared by doctors with women who are weighing the idea of whether to get pregnant while using antidepressants or to continue taking antidepressants when newly pregnant. I can understand the cautious viewpoint. This study is not enough to prove that the antidepressants actually caused the additional miscarriages; the finding could simply have been a correlation. There are also risks in having untreated depression during pregnancy.
But it's also a little disturbing reading some of the quotes out there where physicians are downplaying the possible added risk of miscarriage as being minimal and unimportant. If there really is a causal link, which I hope more research will investigate, I suspect many pregnant moms would not agree that a 68% increase in miscarriage risk was "no big deal," although those with severe depression might decide together with their doctors that the risk is outweighed by the benefits of using antidepressants.
I also think it should be kept in mind that there is also research that shows that miscarriages by themselves are risk factors for depression and that women with a past psychiatric history have higher risk for significant grief reactions, so one has to wonder whether a miscarriage might exacerbate the problem for women with existing depression. As there are rarely answers to what causes any specific miscarriage, there's also a tendency to grasp for explanations that seem to fit as a way to understand what happened. Thus, many moms might be prone to blaming themselves if they find out about this link after-the-fact (even though having a miscarriage while taking antidepressants does NOT mean you can assume that the antidepressants caused the miscarriage). In any case, I hope that women are allowed to make informed decisions on what they want to do and are given all the facts, both for and against the continued use of antidepressants during pregnancy.