L-arginine pathway in neonates with meconium-stained amniotic fluid

To study the arginase, nitric oxide synthase and nitric oxide pathways associated with passage of meconium.

Cord blood samples were collected from 20 newborns with meconium-stained amniotic fluid (MSAF) and from 23 newborns with clear amniotic fluid. Cord blood pH, arginase, nitric oxide synthase and nitric oxide levels were compared between the groups.

The differences between the arginase and nitric oxide measurements of the newborns with MSAF and those with clear amniotic fluid were significant. In the MSAF group arginase levels were significantly lower (p=0.007) and nitric oxide levels were significantly higher (p=0.032) than the clear amniotic fluid group.

Hypoxia may be involved in the pathogenesis of meconium passage due to decreased arginase and increased nitric oxide levels.