Antipsychotic Drugs in Pregnancy Increase Diabetes Risk

Researchers found that out of 360,000 women who gave birth over a four-year span, about four percent of those on antipsychotic drugs developed gestational diabetes. Meanwhile, only 1.7 percent of women who weren't taking antipsychotics were diagnosed with pregnancy-related diabetes.

Dr. Robert Boden, the study's lead author from Uppsala University in Sweden stated that, "It's a very important and difficult area to study, because severe mental disorders - such as schizophrenia and bipolar disorder - often require consistent medication even if a woman is pregnant. So it's very important for us to know all the possible adverse effects from the medications."

Boden and his colleagues wrote that they expected to see a link between the development of gestational diabetes and olanzapine - sold under the brand name Zyprexa - and clozapine - sold as Clozaril.

Boden added that those two drugs are newer antipsychotics and have been linked to weight gain, high cholesterol and increased insulin resistance, according to the authors. "We thought (gestational diabetes risk would be more exaggerated for those treated with the two newer drugs but we were surprised we saw it for all antipsychotics."

For their study, the researchers collected information from various databases on all women who gave birth in Sweden from mid-2005 through the end of 2009. Of those, 169 took olanzapine, clozapine or a combination of the two during pregnancy, 338 took other types of antipsychotics and 357,696 were not on any antipsychotic drugs.

Seven of the women on the newer antipsychotics and 15 on the older versions became diabetic during their pregnancies, compared to 5,970 women not on antipsychotics. That, the researchers say, works out to women on the medications being twice as likely to develop gestational diabetes.

The study, however, cannot prove the drugs caused gestational diabetes. It could be that women on antipsychotics have other traits that leave them more vulnerable to diabetes. Poor diet and lack of exercise, for example, have been tied to the condition.

Practice Pearl:

• The study may not have tracked women for long enough to see a difference in diabetes risk between the newer and older medications.
• There was also no clear link to differences in baby size at birth, since women with gestational diabetes may deliver bigger babies.

Archives of General Psychiatry, online July 2, 2012.