For pregnant patients with severe coronavirus disease 2019 (COVID-19) requiring veno-venous (V-V) extracorporeal membrane oxygenation (ECMO), the ideal timing of delivery is uncertain, particularly when complicated by cardiogenic shock. A 44-year-old patient experienced severe respiratory failure due to COVID-19 at 23 weeks of gestation and underwent V-V ECMO support. Due to severely depressed biventricular cardiac function caused by Staphylococcus aureus bacteremia, the ECMO mode was converted from V-V to veno-arteriovenous (V-AV) ECMO, resulting in improved maternal cardiac function and fetal oxygen supply. At 27 weeks of gestation, she had an unexpected premature rupture of membranes and precipitous vaginal delivery. Despite several complications, she was successfully rehabilitated and discharged after 104 days of ECMO support. Appropriate ECMO implementation, including mode application, together with meticulous multidiscipline discussion on the optimal timing of delivery and prompt decision-making in the event of an unexpected delivery, is critical for maternal and fetal health.