Adiponectin and leptin in maternal serum, cord blood, and breast milk.

Background: The presence of the adipokines adiponectin and leptin in cord blood and placental and fetal tissues suggests a possible role in fetal development.

Methods: We measured concentrations of adiponectin and leptin in maternal serum, cord blood, and breast milk and examined their correlations within a large, population-based study. Between November 2000 and November 2001, we recruited all mothers and their newborns after delivery at the University of Ulm (Ulm, Germany). The current analysis included 766 mothers with available breast milk samples collected 6 weeks postpartum. Adipokine concentrations were measured with commercially available ELISAs (R&D Systems).

Results: Median adiponectin concentrations in maternal serum (n=713), cord blood (n=709), and breast milk (n=766) were 8.6 mg/L, 30.6 mg/L, and 10.9 microg/L, respectively. Median leptin concentrations were 12.8 microg/L in maternal serum, 7.8 microg/L in cord blood, and 174.5 ng/L in breast milk. Whereas increases in leptin concentrations with increasing birth weight, birth weight according to gestational age, and ponderal index were statistically significant in cord blood (all P values<0.0001), cord blood adiponectin was clearly related only to birth weight (P=0.0004). Concentrations of both adipokines were moderately correlated in breast milk and maternal serum (both Spearman rho values were 0.43; P<0.0001).

Conclusions: Concentrations of adiponectin and leptin vary strongly in maternal serum, cord blood, and breast milk, with only moderate correlations between both adipokines in maternal serum and breast milk. The health implications of these patterns warrant further investigation.