Objective: To evaluate whether absolute nucleated red blood cell (RBC) counts are elevated in large-for-gestational-age (LGA) infants of women with gestational diabetes compared with appropriate-for-gestational-age (AGA) infants of women with or without gestational diabetes.
Methods: We compared absolute nucleated RBC counts during the first 12 hours of life in three groups of term, vaginally delivered infants, LGA infants of women with gestational diabetes (n = 20), AGA infants of women with gestational diabetes (n = 20), and AGA infants of nondiabetic women (n = 30). We excluded infants of women with hypertension, smoking, alcohol or drug abuse, and those with fetal heart rate abnormalities in labor, low Apgar scores, hemolysis, blood loss, or chromosomal anomalies.
Results: There were no significant differences among groups in gestational age, gravidity, parity, maternal analgesia, 1- and 5-minute Apgar scores, and lymphocyte counts. Corrected white blood cell counts and hematocrit were significantly higher in LGA infants of women with gestational diabetes than in the other groups. The median nucleated RBC count was significantly higher in LGA infants of women with gestational diabetes (0.56 × 109/L, range 0–1.8 × 109/L) than AGA infants of women with gestational diabetes (0.13 × 109/L, range 0–0.65 × 109/L) and controls (0.0005 × 109/L, range 0–0.6 × 109/L) (P < .001). Multiple regression analysis showed that absolute nucleated RBC count was significantly correlated with birth weight (or macrosomia) and maternal diabetic status (r2 = .25, P < .001 for the multiple regression, contribution of birth weight r2 = .19, and diabetes r2 = .06).
Conclusion: At birth, term LGA infants born to women with gestational diabetes had higher absolute nucleated RBC counts compared with AGA infants born to women with gestational diabetes and controls.
Infants of insulin-dependent diabetic women are at increased risk of intrauterine hypoxia, shown by an increased incidence of abnormal fetal heart rate patterns in labor,1 low neonatal Apgar scores,1 and in extreme cases fetal death.2 One of the consequences of chronic intrauterine hypoxia in infants of insulin-dependent diabetic women is increased erythropoiesis resulting from erythropoietin stimulation. Those infants at birth have increased circulating erythropoietin concentrations,3 increased hematocrit,4,5 and increased circulating nucleated red blood cells (RBC).6 Their neonatal hematocrit level correlates with maternal glycohemoglobin, an index of glycemic control in pregnancy.4
There is little information about the hematologic status of infants of women with gestational diabetes. The purpose of this study was to test the hypothesis that, in infants of women with gestational diabetes, the absolute number of nucleated RBC at birth is higher than that of controls and that the increase in absolute nucleated RBC is more marked in large-for-gestational-age (LGA) infants.