Arterial or venous umbilical pH as a measure of neonatal morbidity?

Although umbilical arterial pH is usually used as a parameter of fetal asphyxia, blood samples are more easily obtainable from the umbilical vein. The relationships of both venous and arterial pH with Apgar scores and neonatal neurological assessment were compared. There was a good correlation between venous and arterial pH and the relationship between venous pH and Apgar scores was similar to that between arterial pH and Apgar scores. Venous pH did not appear to be inferior to arterial pH and Apgar scores in predicting neonatal neurological morbidity.