Clozapine Safety in Pregnancy: A Clinical Study

Background and Hypothesis Pregnant women with persistent schizophrenia and related disorders may require ongoing antipsychotic treatment, including clozapine. However, the potential risks of using clozapine during pregnancy and the postnatal period remain uncertain. Study Design We conducted a nested case-control study using the National Register of Antipsychotic Medication in Pregnancy (NRAMP) database. Our study assessed pregnancy outcomes among Australian women diagnosed with schizophrenia spectrum disorder and treated with clozapine (n = 14) during the first trimester. These women were compared to 2 subgroups: those treated with quetiapine (n = 53) and those not taking any medication (n = 24) during pregnancy. Study Results We observed higher rates of miscarriage in the clozapine group compared to the quetiapine and drug-free groups. The clozapine group had a higher early pregnancy body mass index but lower overall pregnancy weight gain than the other groups. The prevalence of gestational diabetes was significantly higher in the clozapine group. The percentage of vaginal delivery was higher in the clozapine group than in the other 2 groups. Neonatal outcomes such as gestational age, and Apgar scores were similar across groups. The birth weight was lower in the clozapine group compared to the other 2 groups. Conclusions This study suggests that pregnant women taking clozapine and their babies have greater adverse outcomes compared to other groups. Clozapine appears to be associated with a greater risk of miscarriages, maternal gestational diabetes, and lower birth weight. However, the gestational age, Apgar scores, and admission to NICU/SCN were comparable between all groups.