Taking antidepressants during pregnancy

Prenatal treatment for depression does not increase a child’s risk of behavioural or IQ problems from birth through age six, says research published by University of Toronto Professor Irena Nulman.

"This will give women confidence that treating depression during pregnancy is the best choice for both mother and child,” said Nulman.

In a study published Nov.5 in American Journal of Psychiatry, Nulman compared behaviour and IQ of four groups of children to age six years, based on their mothers’ prenatal medical profile. The four groups comprised: mothers with no maternal depression; mothers with untreated maternal depression; mothers with maternal depression treated with SSRIs (selective serotonin reuptake inhibitors); and mothers with maternal depression treated with venlafaxine.

“This answers a question that women who are diagnosed with depression often ask: ‘Is it safe for me to take antidepressants during pregnancy?’ ” said Nulman. “Health care professionals can reassure women that treatment with SSRIs or venlafaxine does not pose additional risk to the unborn child’s future mental health or IQ."

Nulman is a professor of paediatrics at U of T and associate director of the Motherisk Program at The Hospital for Sick Children (SickKids). She specializes in the effects of prenatal exposure to medications and toxins on children’s neurocognitive development.

The length of prenatal treatment also did not make any difference in the child’s later behaviour or IQ, said Nulman.

“Our outcomes show that there is no rationale for women to stop taking antidepressants part-way through pregnancy,” Nulman said, adding maternal depression is itself an important risk factor for post-natal depression after childbirth, which “can have tragic consequences for the woman, her baby, and her family if it is not treated."

The women in all four groups entered the study through their calls to Motherisk, a SickKids’  information and educational service for pregnant women and their health professionals.

The study also found that the children of women who were depressed during pregnancy were at moderately elevated risk of behavioural problems through age six compared to children of healthy mothers, regardless of whether the mothers with depression had been treated during pregnancy or not.

“It’s important to understand that this moderate risk is associated with the depression itself, not with treatment,” said Nulman.

The study is the first to compare IQ of children of mothers who were untreated, treated (with the two medication classes), or healthy. The predictors for IQ in all groups were the child’s sex and the mother’s IQ.

“This aligns with IQ predictors in the general population,” said Nulman.

The next phase of research could compare behaviour and IQ between two siblings of depressed mothers who took medication in one pregnancy and not in the other, Nulman said.

Funding for this research was provided by SickKids Foundation and Wyeth-Ayerst Canada.