Meconium peritonitis refers to rupture of the bowel

Intestine

In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...

 prior to birth, resulting in fetal stool (meconium

Meconium

Meconium is the earliest stools of an infant. Unlike later feces, meconium is composed of materials ingested during the time the infant spends in the uterus: intestinal epithelial cells, lanugo, mucus, amniotic fluid, bile, and water. Meconium is almost sterile, unlike later feces, is viscous and...

) escaping into the surrounding space (peritoneum

Peritoneum

The peritoneum is the serous membrane that forms the lining of the abdominal cavity or the coelom — it covers most of the intra-abdominal organs — in amniotes and some invertebrates...

) leading to inflammation (peritonitis

Peritonitis

Peritonitis is an inflammation of the peritoneum, the serous membrane that lines part of the abdominal cavity and viscera. Peritonitis may be localised or generalised, and may result from infection or from a non-infectious process.-Abdominal pain and tenderness:The main manifestations of...

). Despite the bowel rupture, many infants born after meconium peritonitis in utero

In utero

In utero is a Latin term literally meaning "in the womb". In biology, the phrase describes the state of an embryo or fetus. In legal contexts, the phrase is used to refer to unborn children. Under common law, unborn children are still considered to exist for property transfer purposes.-See also:*...

have normal bowels and have no further issues.

Infants with cystic fibrosis

Cystic fibrosis

Cystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...

 are at increased risk for meconium peritonitis.

Diagnosis

Twenty percent of infants born with meconium peritonitis will have vomiting

Vomiting

Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...

 and dilated bowels on x-rays

Radiology

Radiology is a medical specialty that employs the use of imaging to both diagnose and treat disease visualized within the human body. Radiologists use an array of imaging technologies to diagnose or treat diseases...

 which necessitates surgery.

Meconium peritonitis is sometimes diagnosed on prenatal ultrasound

Obstetric ultrasonography

Obstetric sonography is the application of medical ultrasonography to obstetrics, in which sonography is used to visualize the embryo or foetus in its mother's uterus...

where it appears as calcifications within the peritoneum.