Women who take certain antipsychotic medications and continue the use of these medications through pregnancy may be at increased risk for gestational diabetes, according to new research published online today by the American Journal of Psychiatry.

The authors, from Brigham and Women’s Hospital, Harvard Medical School, Harvard School of Public Health, and Massachusetts General Hospital, presented their findings at a media briefing in New York, where they had come to deliver a presentation at the Annual Meeting of the American Psychiatric Association (APA).

There is a well-established link between some antipsychotic medication and metabolic side effects, such as weight gain and diabetes, which are risk factors for gestational diabetes. Gestational diabetes, a complication of pregnancy, can lead to problems including pre-eclampsia, cesarean delivery, and neonatal hypoglycemia. An estimated 5% to 9% of women develop gestational diabetes during pregnancy. In addition, up to 50% of women with gestational diabetes later develop type 2 diabetes.

The researchers looked at the risk of developing gestational diabetes associated with continued use of several antipsychotic medications, including aripiprazole (Abilify), ziprasidone (Geodon), quetiapine (Seroquel), risperidone (Risperdal), and olanzapine (Zyprexa), during pregnancy.

The study involved a large group of women enrolled in Medicaid who were pregnant, did not have diabetes, and had been taking antipsychotic medication in the 3 months prior to pregnancy. They compared those who continued medication during pregnancy with those who stopped during pregnancy.

The study found that depending on the medication, the absolute risk of gestational diabetes among the study participants continuing medication was 4.2% to 12%; among those stopping medication during pregnancy it ranged from 3.8% to 4.7%.

For two of the five antipsychotic medications examined, olanzapine and quetiapine, there was an increased risk for gestational diabetes compared with women who discontinued these medications, after adjustment for potential confounding variables. There was not an increased risk of gestational diabetes for women taking aripiprazole, ziprasidone, and risperidone.

“It is important to consider alternative explanations for these findings,” said study coauthor Krista F. Huybrechts, MS, PhD, associate professor of medicine, Brigham and Women’s Hospital, Harvard Medical School. “The main concern is potential factors not captured fully in the data, particularly obesity. However, we demonstrated that the imbalance in the obesity prevalence between those continuing treatment and those discontinuing would have to be very high to fully explain the increased risk. This seems unlikely given that all women were treated before the start of pregnancy and we accounted for a broad range of proxy variables.”

The authors note that risk of diabetes is just one factor in a medication decision during pregnancy; other factors include the benefits of the medication and the risks of changing treatment. They suggest that further research on switching antipsychotic medications during pregnancy would help in the making treatment decisions.