Neonatal polycythemia in appropriately grown infants of hypertensive mothers.

Neonatal polycythemia is a frequent finding after pregnancies complicated by diabetes and by maternal hypertension with intrauterine growth retardation (IUGR). It is still unclear if the association of polycythemia with hypertension is the result of IUGR or of hypertension per se. To establish the incidence of neonatal polycythemia in populations at risk, we analyzed the results of hematocrit values obtained from 1592 neonates born consecutively at the Hospital de Clinicas, Buenos Aires. Capillary hematocrit values were obtained by heel stick before 6 h of age. When the values were 65% or greater, new samples were obtained from an antecubital vein. The risk of polycythemia in appropriately grown infants of hypertensive mothers was 12.6-fold greater than the risk in the general population. These data show that maternal hypertension poses a significant risk for polycythemia, regardless of fetal growth. We suggest that, to prevent possible sequela, hematocrit is measured routinely in all infants of hypertensive mothers for prompt diagnosis and treatment.