Review Question - QID 213538

A 29-year-old G1P0 woman at 32 weeks of gestation comes to the emergency department complaining of vaginal bleeding for the past hour. She noticed some blood on the toilet paper when she went to the bathroom an hour ago, but now she is bleeding through her underwear. She denies any trauma, pain, abnormal discharge or odor, fever, or recent infections. The patient mentioned that that during her last ultrasound, the doctor told her that, “there’s an abnormality but not to worry,” but she can’t remember the name of the condition. Her temperature is 100.1°F (37.8°C), blood pressure is 120/70 mmHg, pulse is 86/min, and respirations are 15/min . A fetal heart tracing is obtained and shows a fetal heart rate of 130-140, long-term variability, and appropriate accelerations. What is the most likely explanation for this patient’s presentation?