The Positive Correlation between Cord Serum Retinol-Binding Protein 4 Concentrations and Fetal Growth

Abstract

Background/Aims: Retinol-binding protein 4 (RBP4) has been shown to be associated with insulin resistance and fatty acid metabolism. We hypothesize that RBP4 might play a role in fetal growth and that cord serum RBP4 may act as a marker of fetal growth, independent of fetal insulin levels. Methods: Twenty-one women having fetuses in the top quartile (>75th percentile) of birth weights for gestational age were enrolled into the trial, along with 21 women having fetuses in the bottom quartile (<25th percentile) of birth weights for gestational age. Serum RBP4 and insulin levels were analyzed. Results: Cord serum RBP4 and insulin concentrations were significantly higher in the top quartile group (14.3 ± 3.7 ng/ml, 3.8 ± 5.2 µIU/ml) than in the bottom quartile group (11.3 ± 2.6 ng/ml, 0.9 ± 1.4 µIU/ml; p = 0.004, p = 0.017). Cord serum RBP4 and insulin as well as gestational age (r = 0.744, r² = 0.553, p < 0.001) were significantly correlated with fetal birth weights. Conclusion: Cord serum RBP4 concentrations were higher in subjects with top quartile fetuses than in those with bottom quartile fetuses. Cord serum RBP4 concentrations were significantly correlated with fetal birth weight. These findings may indicate that cord serum RBP4 plays a regulatory role in fetal growth.