Sex, gestational age, and weight dependancy of adult hemoglobin concentration in normal newborns.

We have measured by cation exchange high pressure liquid chromatography adult hemoglobin (HbA) concentration at birth in 6,123 unselected single newborn individuals. Probably because of the high precision of the analytical method used, we could demonstrate clear a relationship between HbA concentration and, respectively, gestational age and birth weight. We also demonstrated a significant difference in the Hb switching process between male and female newborns. Reference percentile distribution curves are given that could be used to define more precisely those children having slow or fast Hb switching.