Cord blood erythropoietin in the presence and absence of labor in normal infants.

To evaluate erythropoietin (Ep) levels in normal labor and cesarean section we studied the cord serum of 111 term pregnancies, divided into three groups: (i) those born by normal vaginal delivery (n = 69); (ii) those delivered vaginally from mothers who were smokers (n = 20); and (iii) those delivered by elective cesarean section (n = 22). The three groups did not differ in maternal age, gestational age, birthweight, infant sex and Apgar scores. No correlation was found between Ep and hematocrit in all three groups of normal terms studied.