Meconium is the first faeces passed by a newborn, in contrast to later faeces it is usually very thick and dark green in colour. It is usually passed after delivery.
Sometimes it may be expelled prior to birth into the amniotic fluid, which is known as “meconium stained liquor”.
It is important that meconium is recognised as it may be a sign of foetal distress and hypoxia (which causes intestinal relaxation and anal sphincter relaxation).
It may be a non-pathological finding in prolonged pregnancies beyond 40 weeks gestation.
The presence of meconium in the amniotic fluid may lead to development of meconium aspiration syndrome (MAS).
MAS is caused by passage of the meconium from the amniotic fluid into the foetal lungs.
This can cause blockage and inflammation of the airways and is associated with significant morbidity and mortality.
Meconium ileus is a condition where the meconium is thickened and causes obstruction of the bowel in the neonate. It is most commonly is an early sign of cystic fibrosis.
Meconium ileus usually presents as bilious vomiting, a distended abdomen and failure to pass meconium within the first 12–24 hours of life.
It is important to recognise the obstruction may leave to bowel perforation, peritonitis , malrotation of the bowel and intestinal atresia.