system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 30-year-old woman, gravida 2, para 1, at 42 weeks' gestation is admitted to the hospital in active labor. Pregnancy has been complicated by gestational diabetes, for which she has been receiving insulin injections. Her first child was delivered by lower segment transverse cesarean section because of a nonreassuring fetal heart rate. Her pulse is 90/min, respirations are 18/min, and blood pressure is 135/80 mm Hg. The fetal heart rate tracing shows a baseline heart rate of 145/min and moderate variation with frequent accelerations and occasional early decelerations. She undergoes an elective repeat lower segment transverse cesarean section with complete removal of the placenta. Shortly after the operation, she starts having heavy uterine bleeding with passage of clots. Examination shows a soft uterus on palpation. Her bleeding continues despite fundal massage and the use of packing, oxytocin, misoprostol, and carboprost. Her pulse rate is now 120/min, respirations are 20/min, and blood pressure is 90/70 mm Hg. Her hemoglobin is 8 g/dL, hematocrit is 24%, platelet count is 120,000 mm3, prothrombin time is 11 seconds, and partial thromboplastin time is 30 seconds. Mass transfusion protocol is activated and a B-Lynch uterine compression suture is placed to control her bleeding. Which of the following is the mostly likely cause of her postpartum complication?
assistant
Lack of uterine muscle contraction