Objective: To determine the umbilical cord blood nucleated red blood cell (UC-nRBC) count in uncomplicated pregnancies delivered by elective cesarean section or delivered vaginally.
Methods: A total of 57-term singleton pregnancies were studied: 33 with elective cesarean sections and 24 with vaginal deliveries. UC-nRBC was analyzed for its nucleated red blood cell counts. A logarithmic transformation of the data was used for statistical analysis.
Results: The mean+/-standard deviation (s.d.) for nucleated red blood cell per 100 white blood cells (nRBC/100WBC) from the elective cesarean section group was 7.8+/-7.4. The vaginal delivery group had a mean value of 9.3+/-10.5, which was not significantly different. A value of 22 nRBC/100WBC defined the upper 95% confidence limit. The correlation between absolute nRBC and nRBC/100 WBC was 0.97.
Conclusion: Although chronic hypoxia is associated with elevated nRBC, the stress of uncomplicated labor does not change the level. This adds credence to its use as a marker for hypoxia preceding labor and delivery.