Transfer of Bromazepam to Cord Blood and Breast Milk: A Case Series of Bromazepam Serum Levels and Outcomes in Newborns and Breastfed Infants

Introduction: Treatment for mental disorders in pregnant and lactating mothers is beneficial for both mothers and children. The potential effects of drugs used for mental health care during pregnancy and lactation on the fetus, neonate, and infant have not been fully elucidated for all drugs. Main issue: Information on placental transfer, transfer into breast milk, and outcomes for newborns and infants born to mothers who used bromazepam during the perinatal period is limited. Management: Three cases in women aged 20 to 40 (one case of bromazepam monotherapy, one case of concomitant zolpidem therapy, and one case of concomitant sertraline therapy) used bromazepam during pregnancy and lactation, and maternal serum and breast milk concentrations of bromazepam were measured through non-interventional sampling. Bromazepam cord blood concentrations were evaluated in two cases and were similar to maternal serum concentrations. Bromazepam elimination from breast milk was similar to elimination from maternal blood. The relative infant dose calculated from breast milk concentrations obtained from lactating women taking 3–6 mg of bromazepam daily ranged from 1.1% to 3.9%. All infants (whose feeding amounts were unknown and who were primarily formula-fed) were healthy, and no issues were identified during their 1-month and 3-month checkups. In the case of zolpidem co-administration, there was an emergency visit after discharge due to reduced crying, but there were no clinical problems. Conclusion: Bromazepam transfers into the placenta and breast milk, with no serious outcomes in neonates and infants, but one infant had unexplained lethargy. Further cases are needed.