Study examines use of antipsychotics early in pregnancy, risk of birth defects

A study of 1.3 million pregnant women suggests antipsychotic medication early in pregnancy was not associated with a meaningful increase in the risk of birth defects when other mitigating factors were considered, although the medication risperidone needs further research, according to a study published online by JAMA Psychiatry.

The use of antipsychotics during pregnancy is increasingly common but clinicians continue to have little information regarding the safety of these drugs on developing fetuses

Krista F. Huybrechts, M.S., Ph.D., of Brigham and Women's Hospital and Harvard Medical School, Boston, and coauthors used a nationwide Medicaid database for their analyses and defined exposure to antipsychotics as filling at least one prescription during the first trimester (90 days) of pregnancy. The authors evaluated typical (older) and atypical (newer) antipsychotic medications.

Among the more than 1.3 million women, 9,258 women (0.69 percent) filled a prescription for an atypical antipsychotic during the first trimester and 733 women (0.05 percent) filled a prescription for a typical antipsychotic, according to the results. The most frequently used atypical antipsychotic was quetiapine, followed by aripiprazole, risperidone, olanzapine and ziprasidone.

Overall, 32.7 per 1,000 births not exposed to antipsychotics were diagnosed with congenital malformations compared with 44.5 per 1,000 births exposed to atypical antipsychotics and 38.2 per 1,000 births exposed to typical antipsychotics, according to the results.

While unadjusted analyses suggested an increased risk of birth defects with atypical antipsychotics, the authors report they observed no significant increased risk of birth defects for typical or atypical antipsychotics after accounting for coexisting mental and physical conditions and their associated behaviors, with the possible exception of risperidone.

Authors warn the small increase in risk with rispedicone must be interpreted with caution because there is not a biological mechanism that readily explains the outcome: "This finding should therefore be interpreted as a potential safety signal that will require follow-up in other studies."

Study limitations include possible misclassification and selection bias, as well as the potential that medications were not taken even though prescriptions were filled.

"Our findings suggest that use of APs [antipsychotics] early in pregnancy does not meaningfully increase the risk for congenital malformation or cardiac malformation, with the possible exception of risperidone. The findings for risperidone should be viewed as an initial safety signal that will require confirmation in other studies," the study concludes.