Umbilical venous leptin concentration and gender in newborns

OBJECTIVE: To investigate the relationship between umbilical venous leptin concentration and gender in 20 pairs of newborns matched 1:1 for birth weig ht and gestational age at sampling. MATERIALS: Blood samples were obtained from 40 women at delivery, identifie d as having an uncomplicated pregnancy. Umbilical venous blood samples were obtained from their newborns (20 males and 20 females) at birth. Specimens were analyzed using a human leptin 125-1 radioimmunoassay. RESULTS: Fetal leptin correlated positively with birth weight (r(s) = 0.541 ; P < .001). Umbilical venous leptin concentrations in female newborns (med ian: 10.7 ng/mL, range: 3.5-34.4 ng/mL). There was not significant correlat ion between maternal and fetal leptin concentrations. Multiple logistic reg ression analysis revealed birth weight and gender to be independent factors influencing fetal cord leptin. CONCLUSION: Our results suggest that in the fetus, as in children and adult s, gender and weight are the major determinants of circulating leptin level s. Copyright (C) 2001 by the Society for Gynecologic Investigation.