Serum leptin concentration in cord blood: relationship to birth weight and gender in pregnancies complicated by pre-eclampsia.

The aim of the study was to investigate cord blood leptin concentrations and their relationship to birth weight and gender in term pregnancies complicated by pre-eclampsia. Cord blood samples were obtained from 52 women, identified as having pre-eclampsia, and their newborns (31 males and 21 females) immediately after birth. Specimens were analyzed using a human leptin 125I radioimmunoassay. The relationship between leptin and anthropometrics was assessed by Spearman correlation. Differences in cord blood leptin levels between male and female infants were tested with the Mann-Whitney U test. The correlation between leptin and gender was computed using the product-moment-biseral correlation analysis for continuous and dichotomous variables. The multiple logistic regression analysis examined influences of sex, birth length, birth weight, birth weight/birth length ratio, ponderal index and maternal leptin as covariates on the fetal cord leptin level. Fetal leptin correlated positively with birth weight, length and weight/length ratio, in the total group and in the male subgroup and additionally with ponderal index in the female subgroup. Cord blood leptin concentrations in female newborns were significantly higher than in male newborns (p = 0.015), and concentrations correlated with gender (r = -0.315; p = 0.023). Multiple logistic regression analysis revealed four potential independent factors influencing fetal cord leptin: gender, birth weight, birth weight/birth length ratio and maternal leptin. In conclusion, cord leptin concentrations in pregnancies complicated by pre-eclampsia correlate positively with birth weight and gender. Leptin concentrations in female newborns are higher compared to male newborns.