Abstract
We report a case of emergent massive meconium peritonitis due to intrauterine volvulus without malrotation. Fetal ascites was detected on a regular ultrasonographic examination, and fetal distress was found on cardiotocographic monitoring. The mother had noticed a slight decrease in fetal movements over the preceding 24 hours. Prenatal magnetic resonance imaging allowed us to distinguish the meconium from fetal peritoneal fluid and to evaluate the degree of compression of the fetal thoracic cavity. The infant was delivered by emergency cesarean section and demonstrated tense abdominal ascites with edema at birth. She required cardiopulmonary resuscitation and immediate paracentesis.