Review Question - QID 214748

A 37-year-old gravida 5 para 5 woman presents with sudden-onset confusion, shortness of breath, and chills. She underwent a scheduled cesarean delivery 1 hour prior for a breech presentation of a healthy newborn boy. She has no significant medical history and takes no medications. Her delivery was uncomplicated other than discomfort when receiving spinal anesthesia prior to delivery and tenderness at the uterine incision site afterward. Her temperature is 99.7°F (37.6°C), blood pressure is 60/30 mmHg, pulse is 140/min, and respirations are 32/min. Pulse oximetry shows an oxygen saturation of 84% on room air. Physical exam reveals a minimally responsive woman with labored breathing. Bibasilar crackles are heard on auscultation. The abdomen is nontender, and there is profuse bleeding from the uterine incision site. On speculum examination, there is significant pooling of bright red blood in the cervix. Which of the following is the most likely etiology for this patient's symptoms?