A 2-hour-old male infant vomits stomach contents and bile. The vomiting continues for 2 days. In addition, abdominal distension is noted, and he is unable to pass meconium (the earliest feces to be eliminated after birth). Which of the following is the most common cause of this condition?

The inability to pass meconium denotes an obstruction of the fetal bowel. Midgut volvulus results in the twisting of the intestines and ultimately obstruction of the small and/or large intestines. Gastroschisis results from an incomplete closure of the lateral folds during the fourth week of development from a defect in the medial plane of the abdominal wall. This results in an epigastric hernia, with viscera that protrude into the amniotic cavity and are covered by amniotic fluid. Failure of recanalization of the ileum is seen with 50% of obstructive lesions of the intestine. This obstruction is caused by stenosis or atresia of the intestines. A remnant of the omphaloenteric duct generally presents as an ileal (Meckel) diverticulum in the proximal portion of the omphaloenteric duct. It normally arises as a fingerlike pouch about 3 to 6 cm long from the antimesenteric border of the ileum and 40 to 50 cm from the ileocecal junction. Nonrotation of the midgut results in the lower portion of the loop returning to the abdomen first, the small intestine sitting on the right side of the abdomen, and the large intestine lying entirely on the left. Most cases are asymptomatic; however, obstruction of the superior mesenteric artery can cause infarction and gangrene of the part of the intestine it supplies.