Background: Olanzapine use has been reported during pregnancy and breastfeeding, but there are no controlled clinical trials assessing the safety of olanzapine exposure to infants and fetuses. The purpose of this report was to review and analyze prospective post-marketing cases of pregnancy and breastfeeding with olanzapine, in order to guide clinicians and women on the use of olanzapine therapy during pregnancy and/or breastfeeding.
Methods: A worldwide safety database maintained by Eli Lilly and Company was searched for all spontaneous-reported data regarding olanzapine use during pregnancy and/or breastfeeding. Cases reported prior to pregnancy outcome were considered to be prospective, and follow-up was pursued after the delivery date to assess outcome.
Results: Outcome data were available for 610 prospectively identified pregnancies during which olanzapine was used. The majority of women had normal births (66%), although premature births were reported in 9.8% and perinatal conditions in 8% of the pregnancies. A total of 102 pregnancies reported olanzapine treatment during breastfeeding. In these infants, the most commonly reported adverse events were somnolence (3.9%), irritability (2%), tremor (2%), and insomnia (2%), although the majority of pregnancies reported no adverse events (82.3%).
Conclusions: The frequency of fetal outcomes in these prospectively identified pregnancies exposed to olanzapine did not differ from rates of outcomes reported in the general population. These data may be useful to help guide clinicians and women decide to continue, or discontinue, olanzapine therapy during pregnancy and/or breastfeeding, but should be considered within the limitations associated with spontaneously reported data. Women should notify their clinicians if they become pregnant or intend to become pregnant while being treated with olanzapine. Because of limited experience in humans, olanzapine should be used in pregnancy only when potential benefit justifies potential risk to the fetus. Olanzapine should only be considered during breastfeeding when the potential benefit justifies the potential risk to the infant.