| Abstract: | Neonatal polycythemia is a well-established perinatal complication in infants of diabetic mothers (IDM). To investigate the regulation of erythropoiesis in these infants, we measured cord blood erythropoietin (EP) levels by a sensitive radioimmune assay and examined the growth of erythroid progenitor colonies in a series of IDM and control infants. Fifteen of 18 diabetic mothers were managed on a protocol emphasizing careful glycemic control throughout pregnancy; 10 had glycosolated hemoglobin values within the normal, nondiabetic range during the third trimester. Cord blood EP was elevated in one of 18 IDM and in two of 13 controls (p = NS). In IDM, cord blood EP values were higher in infants delivered following maternal labor and were inversely correlated with umbilical artery pH (r = -0.72; p = 0.006). Growth of burst forming units-erythroid was similar in IDM and controls in the presence of 0.1 to 2.0 U of exogenous EP per ml of methylcellulose medium. Individual infants tended to respond consistently over the entire range of EP doses tested. The number of burst forming units-erythroid observed did not correlate with cord blood EP, birth weight, or neonatal hematocrits. We conclude that: umbilical cord blood EP levels are generally normal in IDM delivered by mothers in whom good glycemic control is maintained throughout gestation, cord blood EP values are strongly influenced by perinatal events, and the response of erythroid progenitors to EP is intrinsically normal in IDM. These data suggest that polycythemia is an adaptive response in IDM and is not associated with a primary abnormality in erythropoiesis.(ABSTRACT TRUNCATED AT 250 WORDS) |
