Antipsychotic medication use during pregnancy does not put women at additional risk of developing gestational diabetes, hypertensive disorders or major blood clots that obstruct circulation, according to a new study led by researchers at Women's College Hospital and the Institute for Clinical Evaluative Sciences (ICES).

The study, published in BMJ, is the largest to date to examine possible links between newer antipsychotic medications -- such as quetiapine, olanzapine and risperidone -- and medical conditions that often develop during pregnancy or with use of older antipsychotic drug medications.

"Antipsychotic drug use during pregnancy is on the rise, but little is known about possible effects of the newer medications on maternal health or perinatal outcomes like pre-term birth or large birthweight," said Dr. Simone Vigod, a scientist with Women's College Research Institute and an adjunct scientist with ICES.

Antipsychotic drugs are a range of medications that are used for some types of mental distress or disorder - mainly schizophrenia and manic depression (bipolar disorder). They can also be used to help severe anxiety or depression.

The study compared a group of 1,021 pregnant women who took antipsychotics during pregnancy to a group of 1,021 pregnant women of similar of age, income, mental health status and health care utilization who did not take antipsychotics. The researchers found:

• There were no significant differences in risk for gestational diabetes, gestational hypertensive disorders or venous thromboembolism between women who had taken antipsychotic medications during pregnancy and those who had not.
• There were no significant differences in risk for preterm delivery, extremely low birth weights or extremely high birth weights in infants born to women who had taken antipsychotic medications during pregnancy and those who had not.
• Women who used antipsychotic medications during pregnancy were more likely to require labour induction compared to women who did not take an antipsychotic drugs while pregnant.

"The maternal and perinatal medical risks associated with antipsychotic drug use itself during pregnancy appear to be minimal," said Dr. Vigod. "Ultimately, our results support better-informed decision making for women managing mental illness."

The researchers add that there is an ongoing need to carefully assess and monitor pregnant women who are dealing with mental illness.

"Our results are reassuring for women who require antipsychotic medication to maintain their mental health stability during pregnancy, at least with respect to short term maternal and infant outcomes," she added. "Research into longer term child outcomes will be needed to provide a full picture of the long term impact of antipsychotic exposure in a developing fetus."