Gender differences in insulin and C-peptide concentrations at birth using cord blood collection

OBJECTIVE: : To study gender differences in insulin and C-peptide concentrations at birth using cord blood collection. SUBJECTS AND METHODS: This study was conducted in a maternity hospital, in Jammu province of Jammu and Kashmir, India. All women with pregnancy who were hospitalized for delivery were followed. All pregnant ladies who had no medical condition affecting insulin levels, as per history and routine antenatal blood testing, were included in the study. The test for cord plasma insulin and C-peptide was done in 60 (30 males) full-term (≥ 37 completed weeks) normal delivery babies within 4 hours of the collection of samples using the electro-chemiluminescence immunoassay (ECLIA) on Roche elecsys module immunoassay analyzer. Weight of the babies was taken immediately after birth using digital scales. RESULTS: Cord plasma insulin and C-peptide measured in EDTA were compared between boys and girls and also related to birth weight. Girls were lighter (2,830 ± 37 vs. 3,236 ± 46 g; p = < 0.001) but had higher cord insulin (16.48 ± 4.88 vs. 10.53 ± 4.04 µU/mL; p = < 0.001), and C-peptide (2.47 ± 0.66 vs. 0.834 ± 0.26 ng/mL; p = < 0.001) concentrations than newborn boys. CONCLUSION: Female newborn babies have higher cord plasma insulin and C-peptide concentrations than male newborns, despite being smaller, suggesting intrinsic insulin resistance in girls.