A study that examined maternal use of antipsychotic drugs during pregnancy suggests that these medications may be linked to an increased risk of gestational diabetes, according to a report in the July issue of Archives of General Psychiatry.
Severe mental illnesses, such as schizophrenia and bipolar disorder, are usually treated with continuous antipsychotic drugs, "however, the evidence concerning use of antipsychotics during pregnancy is generally lacking or weak," the authors write in the study background.
Robert Bodén. M.D., Ph.D., of the Centre for Pharmacoepidemiology, Karolinska Institutet, Stockholm, and Uppsala University, Uppsala, Sweden, and colleagues used Swedish national health registers for a population-based study that also examined the effects of antipsychotic drugs during pregnancy on fetal growth.
Women who gave birth in Sweden from July 2005 through December 2009, were grouped by filled prescriptions for: (1) the antipsychotics olanzapine and/or clozapine (n=169); (2) other antipsychotics (n=338); or (3) no antipsychotics (n=357,696).
"Gestational diabetes was more than twice as common in mothers who used antipsychotics (seven mothers [4.1 percent] for group 1 and 15 [4.4 percent] for group 2) than in the total population of pregnant women (5,970 [1.7 percent])," according to the study results. The risk increase with olanzapine and/or clozapine was of similar magnitude but not statistical significance, the results indicate.
Women using antipsychotics also had an increased risk of giving birth to a small for gestational age (SGA) infant but, after adjusting for maternal factors, the risk was no longer statistically significant, according to the results.
"In conclusion, maternal use of antipsychotics during pregnancy, regardless of the drug group, is associated with an increased risk of gestational diabetes. The increased risk of giving birth to an SGA infant observed among women treated with antipsychotics during pregnancy is probably an effect of confounding factors, such as smoking," the authors comment.
The results also indicate there were no increased risks of being large for gestational age (LGA) for birth weight or birth length after exposure to olanzapine and/or clozapine, but the risk increased for head circumference.
"Pregnant women treated with antipsychotics should be closely monitored for gestational diabetes and deviating fetal growth," the researchers conclude.
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Arch Gen Psychiatry. 2012;69:715-721.