Peritonitis Meconium peritonitis 2016-02-25T22:28:31Z SNOMEDCT_US:57341009 Peritonitis caused by intrauterine intestinal rupture and spillage of fetal meconium into the fetal peritoneal cavity. Intra-peritoneal meconium usually calcifies, sometimes within 24 hours. Ultrasound findings may include intraabdominal calcifications. UMLS:C0270250