Cardiac operations are occasionally required during pregnancy. Despite a low maternal mortality, fetal mortality remains high. Previous reports have suggested maintenance of high perfusion pressure and flow rate as protective measures to maintain fetal viability. Recent experimental data suggest pulsatile perfusion may help preserve placental hemodynamic function. The successful use of pulsatile bypass to replace the aortic valve in a 25-year-old female at 14 weeks gestation, with both maternal and fetal survival, is presented.