Thirteen patients with Takayasu's arteritis had 30 pregnancies between 1970 and 1982. The 11 pregnancies occurring before the disease became clinically evident were uneventful. Eleven patients had 19 pregnancies after manifestation of the disease. Four ended in abortion, four in cesarean section, and 11 in uneventful vaginal delivery at term. There was no major obstetric problem apart from hypertension, and there was no maternal death directly related to the pregnancy per se. All 15 babies were born without asphyxia and congenital abnormality. The nine with some evidence of intrauterine growth retardation could be predicted by a prognostic score taking into account the timing of therapy, the severity of the hypertension, and the extent of arterial involvement.