Paralytic ileus in a fetus–neonate after maternal intake of benzodiazepine

Paralytic ileus of the small bowel was diagnosed in a fetus at 32 weeks' gestation after referral because of polyhydramnios. The mother had taken clonazepam, a benzodiazepine, and carbamazepine during the entire pregnancy for epilepsy. All known causes for the ileus were ruled out and at 20 months the boy has developed normally. We conclude that maternal anticonvulsant drug intake was very likely the cause of the paralytic ileus. This side-effect is known in experimental and clinical pharmacology but has not yet been described in human fetuses.