Study Links Effexor to Miscarriage Risk

Montreal, QuebecA new study has linked Effexor (known generically as venlafaxine) to an increased risk of miscarriage. Although the risk of miscarriage in women who took Effexor is not as high as in those who take Paxil (paroxetine), the risk is still higher than among women who take no antidepressant at all.

The study, conducted at the University of Montreal, found that the use of selective serotonin reuptake inhibitors (SSRIs) early in pregnancy was linked to a 68 percent increase in the risk of miscarriage before the 20th week. According to Montreal newspaper The Gazette, the overall rate of miscarriage is approximately 20 percent. Among women taking antidepressants, especially Effexor or Paxil, the risk of miscarriage increases to 34 percent.

The highest risk of miscarriage was seen in women who took Paxil early in pregnancy. Women who took Paxil while pregnant had a 75 percent relative increased risk of miscarriage over women who did not take antidepressants. Women who took Effexor while pregnant had double the risk of miscarriage.

The increased risk of miscarriage was also seen in women who took higher doses or combination of antidepressants.

Published in the Canadian Medical Association Journal, the study examined records of women who miscarried in Quebec between 1998 and 2003. Researchers found that 5.5 percent of the women who had a miscarriage filled a minimum of one prescription for an antidepressant during pregnancy. By comparison, 2.7 percent of control subjects experienced a miscarriage but did not take an antidepressant.

Other studies have linked Effexor to an increased risk of birth defects, including congenital heart defects and persistent pulmonary hypertension of the newborn. Further side effects suggested by studies include developmental delays, withdrawal symptoms and a higher rate of behavioral signs, including problems with the central nervous system.

Unlike Paxil, Effexor is a serotonin-norepinephrine reuptake inhibitor (SNRI), meaning it prevents the reuptake of both serotonin and norepinephrine, increasing the levels of those two neurotransmitters in the brain. Effexor is used to treat major depression and other mood disorders.

The study does not say absolutely that taking an antidepressant during pregnancy causes a miscarriage; it only shows that there is an association between taking an antidepressant while pregnant and an increased risk of miscarriage.

Women who are pregnant and taking an antidepressant should not discontinue medication without speaking to their doctor. Although there are risks associated with taking antidepressants during pregnancy, there are also risks to having untreated depression while pregnant. Those risks extend to both mother and baby.