RESUMEN
Congenital transmesenteric hernias are uncommon and are a rare cause of bowel obstruction, which is even rarer in pregnant woman. Because of the lack of specific symptoms or reliable sensitive markers, it is difficult to diagnose internal hernia at early stage, therefore resulting in the delay of surgical intervention and a high mortality rate, especially in pregnant woman. We report a case in which a woman presenting at 16 weeks` gestation was admitted with symptoms of nausea, vomiting and left upper abdominal pain similar to her first-trimester morning sickness. Nephrolithiasis of the left kidney detected by ultrasound may lead to early incorrect diagnosis. Due to the patient`s concern about known adverse effects of ionizing radiation on the fetus, computed tomography was postponed until abdominal pain worsened, coffee color gastric contents vomited and anus stopped exhaust and defecation 12 hours later. Low dose CT plain scan showed features of small bowel obstruction by an internal hernia. Emergency exploratory laparotomy revealed a mesenteric defect of the left colon with a 30 cm long jejunal herniating distal to 10 cm of the ligament of Treitz. The involved small bowel was strangulated and gangrened, necrotic segmental resection and end to end anastomosis were performed subsequently, and the mesenteric defect was then successfully repaired with sutures.