Relation between nucleated red blood cell count in umbilical cord and the obstetric and neonatal outcomes in small for gestational age fetuses and with normal Doppler velocimetry of umbilical artery

Abstract

To analyze the obstetrical and neonatal outcomes of pregnancies with small for gestation age fetuses after 35 weeks based on umbilical cord nucleated red blood cells count (NRBC). NRBC per 100 white blood cells were analyzed in 61 pregnancies with small for gestation age fetuses and normal Doppler findings for the umbilical artery. The pregnancies were assigned to 2 groups: NRBC≥10 (study group, n=18) and NRBC<10 (control group, n=43). Obstetrical and neonatal outcomes were compared between these groups. The χ(2) test or Student's t-test was applied for statistical analysis. The level of significance was set at 5%. The mean ± standard deviation for NRBC per 100 white blood cells was 25.0 ± 13.5 for the study group and 3.9 ± 2.2 for the control group. The NRBC≥10 group and NRBC<10 group were not significantly different in relation to maternal age (24.0 versus 26.0), primiparity (55.8 versus 50%), comorbidities (39.5 versus 55.6%) and gestational age at birth (37.4 versus 37.0 weeks). The NRBC≥10 group showed higher rate of caesarean delivery (83.3 versus 48.8%, p=0.02), fetal distress (60 versus 0%, p<0.001) and pH<7.20 (42.9 versus 11.8%, p<0.001). The birth weight and percentile of birth weight for gestational age were significantly lower on NRBC≥10 group (2,013 versus 2,309 g; p<0.001 and 3.8 versus 5.1; p=0.004; respectively). There was no case described of 5th minute Apgar score below 7. An NRBC higher than 10 per 100 white blood cells in umbilical cord was able to identify higher risk for caesarean delivery, fetal distress and acidosis on birth in small for gestational age fetuses with normal Doppler findings.