A 23-year-old primigravid woman at 14 1/7 weeks of gestation arrived at the emergency department with abdominal pain. Two months earlier, she began having intermittent pain and constipation. She had performed an enema three times and had received intermittent medicated laxatives for 2 months from local clinics. The patient reported having had severe constipation for 7 days 1 year perviously. Her past medical, surgical and family histories were negative. On physical examination, she was 155 cm tall and weighed 38 kg. She had diffuse abdominal tenderness without rebound tenderness. Her bowel sounds were normal. She displayed intermittent colicky pain, which subsided only with opioid treatment. She was treated with stool softeners and laxatives. One day after admission, the patient’s hemoglobin was 9.7 g/dL, hematocrit was 27.1%, and white blood cell count was 9,840/microliter. We prescribed rehydration, electrolyte control, and analgesics for intermittent severe pain. Three days after admission, she developed night fevers (maximum temperature 38°C) and sweating. Considering our differential diagnosis, which included infection and connective tissue disorder, we ordered various other laboratory studies including erythrocyte sedimentation rate; urine culture; hepatitis A, B, and C evaluation; antinuclear antibody testing; and rheumatic factor; all were within normal limits. The C-reactive protein level was elevated to 3.40 mg/dL. We began cefotetan intravenously 4 days after admission; the physician recommended she receive nothing by mouth. Six days after admission, a magnetic resonance imaging scan revealed marked dilatation (6-cm diameter) of the transverse and descending colon (Fig. 1). Seven days after admission, glutamyl oxaloacetic transaminase and glutamyl pyruvic transaminase levels increased to 102 and 134, respectively. Eight days after admission, the C-reactive protein level increased to 11.73 mg/dL, and upper endoscopy revealed gastritis. Colonoscopy revealed multiple colon ulcers, colonic atony, and colonic inertia (Fig. 2). The physician and patient agreed to radiologic studies to evaluate possible colon perforation. An X-ray computed tomography scan revealed a sigmoid colon collapse with fecal content; the transverse colon was 10 cm in diameter, and the colon was dilatated from the cecum to the transverse colon (Fig. 3). No perforation was seen. Ogilvie syndrome (acute colonic pseudo-obstruction) then was suspected. Nine days after admission, we performed a diatrizoate meglumine and diatrizoate sodium (Gastrografin) enema. Rectal and nasogastric tubes were placed for decompression, and erythromycin, piperacillin, and tazobactam were given intravenously. (We did not prescribe neostigmine because it is contraindicated in a setting of gastrointestinal ulcers.) The From the Department of Obstetrics and Gynecology, College of Medicine, Soonchunhyang University, Bucheon, Republic of Korea.