Failure to pass meconium: diagnosing neonatal intestinal obstruction.

[megacystis-microcolon-intestinal hypoperistalsis syndrome]

Timely passage of the first stool is a hallmark of the well-being of the newborn infant . Failure of a full-term newborn to pass meconium in the first 24 hours may signal intestinal obstruction . Lower intestinal obstruction may be associated with disorders such as Hirschsprung 's disease , anorectal malformations , meconium plug syndrome , small left colon syndrome , hypoganglionosis , neuronal intestinal dysplasia and megacystis-microcolon -intestinal hypoperistalsis syndrome . Radiologic studies are usually required to make the diagnosis . In addition , specific tests such as pelvic magnetic resonance imaging , anorectal manometry and rectal biopsy are helpful in the evaluation of newborns with failure to pass meconium .