Maternal and fetal serum leptin levels and their association with maternal and fetal variables and labor: A cross-sectional study.

Background: Leptin is a polypeptide hormone that may be implicated in the pathogenesis of various disorders during pregnancy. We sought to determine serum leptin levels among pregnant women and their fetuses and to investigate their association with fetal and maternal variables.

Method: 452 pregnant women who attended to labor ward between January 2020 and August 2020 were included in the study. Serum leptin concentrations were measured using enzyme-linked immunosorbent assay method. Mann-Whitney test and Spearman's correlation test were used for statistical analysis. A multivariate linear regression analysis was then performed. Significance level was considered at alpha <0.05.

Results: The median maternal and fetal serum leptin levels were 6.42 [4.16-8.51] ng/mL and 2.9 [1.03-5.36] ng/mL respectively. There was no significant correlation between maternal and fetal serum leptin levels ( = 0.064). Maternal serum leptin levels correlated positively with maternal body mass index (BMI) ( = 0.117,  = 0.005). Besides, maternal serum leptin levels were significantly higher in nulliparous women (7.57 [4.45-9.30] ng/mL vs. 6.22 [4.02-8.30] ng/mL,  = 0.037) and in women who were in active labor (6.83 [4.39-8.92] ng/mL vs. 6.25 [4.04-8.30] ng/mL,  = 0.047). Fetal serum leptin levels were significantly higher in large for gestational age (LGA) fetuses (4.81 [2.13-7.22] ng/mL vs. 2.80 [0.96-5.16] ng/mL,  = 0.003) and in fetuses with preterm premature ruptures of membranes (PPROM) (5.23 [2.42-8.07] ng/mL vs. 2.86 [1.00-5.23] ng/mL,  = 0.021).

Conclusion: Maternal serum leptin levels were influenced by maternal BMI, parity and labor. Fetal serum leptin levels were higher among LGA fetuses and in fetuses with PPROM.