Three women with neurohypophyseal diabetes insipidus, treated for prolonged periods, including pregnancy, with L-deamino-8-d-arginine vasopressin, gave birth in our hospital. Two of the infants had severe congenital heart disease, one of which was associated with trisomy 21. The third baby, born prematurely, presented with mild intrauterine growth retardation; at the age of 21 months, the boy had severe failure to thrive, hypotonia, and motor retardation. These three cases raise doubts as to the safety of diabetes insipidus or its treatment in pregnancy.