To test the hypothesis that maternal adverse childhood experiences (ACEs) impact are associated with fetal adrenal development in a sex-specific manner, we recruited pregnant women (N = 147) for a longitudinal study and dichotomized them into high and low ACE groups based on the ACE Questionnaire. At approximately 21.5 (SD 1.4) weeks and 29.5 (SD 1.4) weeks gestation, participants underwent three-dimensional ultrasound to measure fetal adrenal volume, which was adjusted for fetal body weight (waFAV). Mother’s cortisol awakening response was measured across three consecutive days at approximately 18 weeks gestation.