Leptin concentrations in maternal serum and cord blood: relationship to maternal anthropometry and fetal growth

Objective To determine 1. the relationship between maternal serum leptin concentrations and maternal anthropometry and 2. the relationship between cord serum leptin concentrations at birth and neonatal anthropometry. Design Prospective cohort study of fetal growth in low-risk pregnancies. Setting University teaching hospital. Sample Thirty-nine women and their babies taking part in a fetal growth study. Methods Blood was taken from the women between 10-20 weeks of gestation and from the umbilical cord of their babies at delivery. Serum leptin was measured by radio-immunoassay. Maternal anthropometric measurements were recorded at booking. Neonatal anthropometric measurements were recorded within 48 hours after delivery. Linear regression analysis was used to explore the relationship between serum leptin concentrations and anthropometric measures and multiple regression analysis then applied to determine which variables remained independently associated with leptin. Results The median (range) leptin concentration in maternal serum was 11.8 ng/mL(1.7-39.7) and in cord blood was 4.2 ng/mL (0.6-21.4). Maternal leptin levels correlated with maternal weight, body mass index, midarm circumference and skinfold thickness, but not with birthweight, placental weight or maternal height. Body mass index and midarm circumference remained significant after multiple regression analysis. Cord leptin levels correlated with birthweight, birthlength, placental weight and skinfold thickness but not with ponderal index. Birthweight and subscapular skinfold thickness remained significant after multiple regression analysis. Cord leptin concentrations did not correlate with maternal leptin concentrations. Conclusions We suggest that there are very strong associations between maternal leptin and maternal adiposity in pregnancy, and between cord leptin at delivery and birthweight, as well as other anthropometric markers of fetal growth.