The effect of prolonged rupture of membranes on circulating neonatal nucleated red blood cells.

OBJECTIVES: To test the hypothesis that absolute nucleated red blood cells (ANRBC) counts are higher at birth in infants who were born after prolonged rupture of membranes (PROM, >24 hours). STUDY DESIGN: Retrospective study of 31 infants admitted to the neonatal intensive care unit who were born after PROM, and pair matched for gestational age and Apgar scores with 31 no PROM controls. Venous ANRBC counts were obtained within 1 hour of life. RESULTS: Groups did not differ in birthweight, gestational age, Apgar scores, and platelets counts. The ANRBC counts and hematocrit were significantly higher in infants who were born after PROM than in controls. CONCLUSIONS: Infants born after PROM have higher ANRBC counts at birth than control infants. We suggest that increased fetal erythropoiesis exists in infants who are delivered after PROM. If correct, our interpretation supports the theory that fetal hypoxia and/or ischemia may result from PROM.