Cardiopulmonary bypass (CPB) during pregnancy is associated with a maternal mortality similar to the nonpregnant population; however, fetal morbidity and mortality are high. Various strategies to improve fetal survival have been advocated. Alteration in uterine artery flow velocity has been reported during nonpulsatile CPB; however, roller pump-generated pulsatile flow for CPB remains controversial. We report use of the intra-aortic balloon pump (IABP) in two cases of pregnancy. In the first, the IABP was inserted after termination of a long bypass, specifically in an attempt to improve uterine perfusion and thereby relieve a profound fetal bradycardia. In the second, the IABP was used electively to provide pulsatile flow during the bypass period primarily to benefit fetal hemodynamics.