Gestational diabetes may be more likely with antipsychotic use

By Sally Robertson, B.Sc.Jul 10 2012

Women who take antipsychotic medication during pregnancy may be at an increased risk for developing gestational diabetes, report researchers.

Such individuals should be closely monitored for gestational diabetes and deviating fetal growth, advise Robert Bodén (Uppsala University, Sweden) and colleagues.

According to information recorded in three Swedish national health registers, seven (4.1%) of 169 women prescribed olanzapine and/or clozapine during pregnancy, and 15 (4.4%) of 338 prescribed any other antipsychotic developed gestational diabetes, compared with only 5970 (1.7%) of 357,696 women who were not prescribed antipsychotics.

"Olanzapine and clozapine have been associated with substantial weight gain, hyperlipidemia, and increased insulin resistance," say the authors, who explain that there is concern that these drugs may have anabolic fetal growth effects and increase the risk for gestational diabetes.

As reported in the Archives of General Psychiatry, univariate analysis showed that compared with nonuse, antipsychotic use was associated with more than twice the risk for gestational diabetes, at an odds ratio (OR) of 2.44 for those who took olanzapine and/or clozapine, and an OR of 2.53 for those on any other antipsychotic.

After adjustment for birth order and maternal age, country of birth, cohabitation, smoking, and height, the ORs remained of similar magnitude, at 1.94 for those on olanzapine and/or clozapine and 1.77 for those on any other antipsychotic, although the former was no longer significant.

After adding early pregnancy body mass index to the model, both ORs were slightly attenuated and both were no longer significant.

"Our hypothesis of a pharmacological effect… was supported by the increased risk of gestational diabetes being almost unaffected after adjustment for maternal factors," writes the team.

The researchers also found that infants exposed to antipsychotics were more than twice as likely to be small for gestational age, regardless of medication group, than unexposed infants. However after adjustment for maternal factors, this risk estimate was no longer significant, suggesting it was probably an effect of confounding factors such as smoking, says the team.

Conversely, the authors did find that exposure to olanzapine and/or clozapine increased the risk for giving birth to a child with macrocephaly - a head circumference that is large for gestational age.

They describe this finding as "surprising," and say this observation deserves to be investigated further.

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