Antidepressants Linked to Miscarriage, Effexor Implicated

Montreal, PQNew research out of Canada is warning expectant moms that they run a far greater risk of losing their babies through miscarriage if they take antidepressants like Effexor during pregnancy.

Researchers at the Universite de Montreal (UdeM) found that antidepressant use during pregnancy is associated with a 68 percent relative increase in the risk for miscarriage. Overall, researchers found that 20 percent of all pregnancies miscarried.

The results only add to the debate over the benefit / risk ratios inherent with using antidepressants while pregnant. In some cases, doctors fear that a woman being treated for severe depression will put herself and her unborn child at greater risk if she stops taking the medication or reduces her dosage in an attempt to mitigate the potential risk for the baby.

The Canadian researchers identified two types of antidepressants that were considered especially dangerous: paroxetine, and venlafaxine (Effexor). The combined use of different drug classes was also found to present a risk.

According to the 6/1/10 edition of the Montreal Gazette, the research team used data from the Quebec Pregnancy Registry, which includes all Quebec pregnancies since 1997. They compared 5,124 women who miscarried before their 20th week to 51,240 matched "controls"—women from the registry who didn't miscarry.

A total of 284, or 5.5 percent, of women who miscarried had at least one prescription for an antidepressant filled during their pregnancy, compared to 2.7 percent of the controls.

"If you take antidepressants, your risk will go from 20 percent to 34 percent—so one out of three," says senior author Dr. Anick Berard of the UdeM and director of the Research Unit on Medications and Pregnancy at CHU Ste. Justine.

After grouping women according to specific selective serotonin reuptake inhibitors (SSRIs), researchers found a 75 percent relative increase in risk with paroxetine alone. They also found a doubling of risk with venlafaxine (Effexor).

Higher daily doses of both drugs were also associated with a greater risk of suffering a spontaneous abortion.

According to the Montreal Gazette, Effexor (venlafaxine) has been shown to increase the risk that women will have babies that are small for gestational age.

"We still don't know if this is because of the depression or the antidepressants," said Adrienne Einarson, assistant director of the Motherisk Program at the Hospital for Sick Children in Toronto. "I can tell you, [depressed pregnant women] are untreated quite often because they get pregnant and their physicians think, maybe less is best, so they cut down the dose, so they're not being treated really."

The Motherisk program reportedly found almost identical results in a study last fall. Einarson says the risk is "very, very small." Depression occurs in up to 15 percent of all pregnant women; about four percent use antidepressants at some point in their first trimester.