Nuchal cords and neonatal outcome.

To assess the significance of nuchal cords, 110 affected woman-infant pairs at term gestation were compared with 110 control pairs. Newborns with a nuchal cord had an increased prevalence of umbilical artery acidemia (22 of 110 versus 13 of 110; P less than .05) and more variable fetal heart rate (FHR) decelerations in the first stage of labor (mild = 41 versus 20; P less than .0001; moderate-severe = 21 versus 5; P less than .0001) and the second stage of labor (moderate-severe = 46 versus 21; P less than .0001). In newborns with a nuchal cord, the umbilical artery acidemia was usually mixed (68%) or respiratory (23%) in origin, and pure metabolic acidemia was infrequent (9%). We conclude that nuchal cords are associated with an increased prevalence of variable FHR decelerations in the first and second stages of labor and with an increased incidence of umbilical artery acidemia.