A 31-year-old gravida 2, para 1 patient of 36 weeks’ gestation had undergone a laparoscopic Roux-en-Y gastric bypass (RYGB) 4 years ago, resulting in prepregnancy weight loss of 70 kg, or 128% of her excess weight. She awakened with severe lower back pain, abdominal pain, nausea, and vomiting. She came to the emergency department with 10/10 abdominal pain but no fever, chills, vaginal bleeding, or rupture of membranes. Her abdominal examination revealed diffuse tenderness and guarding. She was initially diagnosed as having preterm labor and was given antibiotics, steroids, an epidural catheter for pain management, and intravenous fentanyl as needed. She delivered a healthy baby without complications, but her severe abdominal pain, nausea, and vomiting persisted. Thirty-six hours after her initial presentation, she still had rebound tenderness in the left side of the abdomen. She was afebrile, blood pressure was 104/77 mm Hg, and heart rate was 152/min. White blood cell count was 10.7 ×109/L; anion gap, 13 mEq/L; and lactate dehydrogenase level, 131.7 U/L (2.2 μkat/L). A computed tomography (CT) scan of the abdomen and pelvis with oral and intravenous contrast revealed mesenteric vascular compromise (Figure 1); after the scan, the patient had hematemesis.