OBJECTIVE: The study goal was to examine the impact of commonly prescribed antiemetic medications in pregnancy on neurobehavioral and obstetric outcomes. STUDY DESIGN: Five hundred thirty-three women accounting for 550 live births (17 multiple gestations) enrolled before 16 weeks’ gestation participating in an observational longitudinal study of stress and pharmacologic exposure in pregnancy at Emory Women’s Mental Health Program were included in this study. Maternal report of exposure to medications was documented by weeks of use. Obstetric and neonatal data were obtained from medical records. The Neonatal Behavioral Assessment Scale was completed by certified raters at age 7 days. The Child Behavior Checklist (CBCL) was completed by the mother between 17 and 66 months of age. Comparison of groups was conducted using chi(2) and Wilcoxon rank-sum tests. Spearman correlation analysis was used for CBCL percentile scores to evaluate duration of exposure. RESULTS: The exposed group (n = 143) was comprised of children whose mothers received promethazine or ondansetron during pregnancy. Unexposed children (n = 407) were used for comparison. Neonatal Behavioral Assessment Scale data 7 days (range, 2-77) was available on 345 infants (exposed n = 102; unexposed n = 243), and a total of 247 CBCLs (exposed n = 51; unexposed n = 196) at 29 (range, 17-66) months of age. No significant differences were seen using Neonatal Behavioral Assessment Scale and CBCL. Statistically significant differences were seen in gestational age at delivery (0.3 weeks) and birthweight (110 g). CONCLUSION: No clinically significant adverse neurobehavioral effects or obstetric outcomes were identified. This is reassuring as promethazine and ondansetron are commonly prescribed during pregnancy.