Early postnatal growth in preterm infants and cord blood leptin.

Although circulating leptin and insulin concentration is linked to intrauterine growth, fetal development and birth weight in full-term infants, there has been no enquiry into the influence of cord blood insulin and leptin for catch-up growth in preterm infants. The study evaluated the association of cord blood leptin with growth and weight gain of 96 premature babies during 6 months (corrected age). The temporal changes of anthropometric indexes over this period were calculated by repeated random regression (PROC MIXED) using SAS. Cord blood leptin was negatively associated with the rate of change in BMI (p=0.01) and length (p<0.001), from birth until 64 postnatal weeks. Insulin was positively associated with the change rate in BMI (p=0.03); however, this disappeared when adjusted for birth weight. For the first time, the association between lower leptin levels with greater catch up growth is shown for both BMI and length among preterm children. In conclusion, leptin levels at birth, but not insulin levels, predict growth rates.