Background: Entanglement of the umbilical cord around fetal neck has been reported to be associated with birth asphyxia. On the other hand, current evidence suggests that umbilical arterial pH analysis provides the most sensitive reflection of birth asphyxia. In this study we aimed to evaluate and compare the umbilical arterial hydrogen-ion concentration (pH) and to analyze the blood gases of neonates with or without nuchal cord.

Methods: In this cohort study, 92 newborns with and 95 without nuchal cords were enrolled at Shahid Akbar Abadi Hospital in Tehran, Iran between the years 2009 and 2010. From each newborn an umbilical arterial blood sample was collected to measure pH, base excess and blood gases.

Results: There were no statistically significant differences between newborns with or without nuchal cord regarding maternal age, gestational age, and history of pregnancy. The mean pH in the newborns with nuchal cord (7.21±0.1) was significantly less than the value in the newborns without the cord (7.28±0.1), (P<0.001). In contrast, the mean base excess in the newborns with nuchal cord was more than the ones without the cord (P<0.001). Seven newborns (7.9%) in the group with nuchal cord passed meconium during labor while only one (1%) newborn did so in the other group.

Conclusion: Our finding showed that nuchal cord had a significant relationship with acidosis in newborns with nuchal cord. However, this finding needs further investigation to reach a common conclusion.