Context: Knowledge about the effects of exposure to the newer antipsychotics during pregnancy is limited.
Objective: To investigate the effects of maternal use of antipsychotics during pregnancy on gestational diabetes and fetal growth.
Design: Population-based cohort study comparing women exposed and not exposed to antipsychotics during pregnancy. Exposure was defined as prescriptions filled.
Setting: Swedish national health registers.
Participants: All women giving birth in Sweden from July 1, 2005, through December 31, 2009, grouped by filled prescriptions for (1) olanzapine and/or clozapine, the most obesogenic and diabetogenic antipsychotics (n = 169), (2) other antipsychotics (n = 338), or (3) no antipsychotics (n = 357,696).
Main outcome measures: Odds ratios (ORs) with 95% CIs for gestational diabetes and being small for gestational age (SGA) and large for gestational age for birth weight, birth length, and head circumference.
Results: Exposure to other antipsychotics was associated with an increased risk of gestational diabetes (adjusted OR, 1.77 [95% CI, 1.04-3.03]). The risk increase with olanzapine and/or clozapine was of similar magnitude but not statistical significance (adjusted OR, 1.94 [95% CI, 0.97-3.91]). Infants exposed to either group of antipsychotics had increased risks of being SGA on birth weight, whereas only exposure to other antipsychotics yielded increased risks of being SGA for birth length and head circumference. None of the risks for SGA measurements remained significant after adjusting for maternal factors. There were no increased risks of being large for gestational age for birth weight or birth length after exposure to olanzapine and/or clozapine, but the risk increased for head circumference (OR, 3.02 [95% CI, 1.60-5.71]).
Conclusions: Women who used antipsychotics during pregnancy had increased risks of gestational diabetes. The increased risks of giving birth to an SGA infant seemed to be an effect of confounders, such as smoking. Except for macrocephaly, olanzapine and/or clozapine exposure was not associated with anabolic fetal growth.