Pregnant women who take atypical antipsychotics such as clozapine, olanzapine, or risperidone, do not appear to be at increased risk of giving birth to a child with a birth defect, Canadian investigators report.

Many women of childbearing age suffer from schizophrenia and other mental illnesses that require them to take antipsychotic medications while pregnant, Dr. Adrienne Einarson, from the Hospital for Sick Children, in Toronto, and colleagues point out.

Atypical antipsychotics have been on the market since the mid-1990s, but data are lacking on there use during pregnancy.

In the current study, Einarson’s team looked at the pregnancy outcomes of 151 women who had taken an atypical antipsychotic in the first trimester of pregnancy.

A total of 60 women had been exposed to olanzapine, 49 to risperidone, 36 to quetiapine, and 6 to clozapine. The outcomes in these women were compared to outcomes in a group of pregnant women who had not been exposed to these medications.

According to the team, rates of major malformations, Miscarriage and stillbirths were similar in the exposed group and non-exposed comparison group.

Among women who used atypical antipsychotics, there were 110 live births (72.8 percent), 22 spontaneous abortions (14.5 percent versus 8.6 percent in the comparison group), 15 “therapeutic” abortions (9.9 percent versus 1.3 percent), and 4 stillbirths (2.6 percent).

One major malformation was observed in the group exposed to atypical antipsychotic drugs compared with two in the comparison group.

Overall, the average birth weight among babies born to women in the exposed group was no different from that in the comparison group. However, 10 percent of babies in the exposed group were low birth weight, compared with 2 percent of babies in the non-exposed group.

Reporting these findings in the Journal of Clinical Psychiatry, the authors say it’s best to strive for “optimal control” of psychiatric disorders throughout pregnancy and the postpartum period.

Nonetheless, “all pregnancies in which a woman requires an antipsychotic medication should be considered high risk because of the mother’s diagnosis, and both mother and fetus should be carefully monitored throughout the pregnancy and thereafter,” they advise.

SOURCE: Journal of Clinical Psychiatry, April 2005.