Pregnancy carries significant physiological changes that demand more cardiac output, so structural cardiac disease can cause life-threatening complications. A woman had rheumatic mitral stenosis and underwent mitral valve replacement (MVR) with bioprosthesis 8 years prior to admission. She presented with dyspnea and leg edema at 30 weeks of gestation. Severe mitral stenosis caused by xenograft failure was noted on echocardiography. Management was conservative until a sudden onset of hemodynamic compromise requiring emergency redo MVR under normothermic cardiopulmonary bypass with intra-aortic balloon pump. Monitoring of fetal heartbeat and uterine contractions showed no significant abnormalities and the woman gave birth to a full-term baby by Cesarean section with postoperative warfarin therapy.