The incidence of bacterial endocarditis (BE) during pregnancy is about 0.01%, while maternal and fetal mortality rates due to BE are 22% and 15%, respectively. Fetal survival is <15% until week 25 of gestation, and cesarean delivery is recommended before cardiopulmonary bypass in the third trimester. The case is described of a 24-year-old woman (a known drug addict), gravida 1, para 0, at week 22 of gestation, with an acute mitral valve endocarditis caused by Staphylococcus aureus. Following urgent mitral valve replacement, the strategy for fetal survival involved reducing the hemodilution and scavenging the cardioplegia solution from the right atrium, avoiding deep hypothermia to minimize rewarming, and maintaining a high pump flow rate (>2.5 l/min/m2) with a mean perfusion pressure of 70 mmHg, using pulsatile perfusion. The patient had an uneventful postoperative course, and at 34 weeks' gestation a normal newborn of 1780 g was delivered by cesarean section. No controlled clinical trials using extracorporeal circulation during pregnancy have been conducted, and reports are limited to single cases. A strategy was proposed to manage the present case of uncontrolled maternal BE at an early gestational age, by addressing several factors that would influence the outcome for both mother and baby.