A Study on Relationship of Serum Leptin Levels with Body Weight, Body Mass Index, and Percent Body Fat in the Mothers and Their Infants

ABSTRACT

To estimate whether serum leptin has any effects on body composition during the lactational and postnatal periods, we investigated the relationship of serum leptin levels and anthropometric parameters at right after delivery and 16 weeks after delivery in mothers and their infants. Subjects who signed the concent form, participated in this study were recruited from K university hospital. Characteristics of the subjects ( age; 31.0 +/- 4.2 yr, gestation period; 39.5 +/- 1.0 wk) were investigated and anthropometric parameters ( weight, height, body mass index and percent body fat for mothers, and weight, height, head circumference, chest circumference, and Kaup index for infants) were measured. Serum leptin levels of mothers and their infants also measured. Mean maternal serum leptin levels were 9.9 +/- 8.2 ng/ml and 9.1 +/- 7.2 ng/ml at right after delivery and 16 weeks after delivery, respectively showing no significant differences. Mean infant's serum leptin levels at birth ( 1.8 +/- 0.4 ng/ml) were significantly lower than that of at 16 weeks after birth ( 4.2 +/- 0.8 ng/ml)(p < 0.001) . Leptin levels of male infants were not different from those of female infants. There were no correlations between the maternal serum leptin levels with their body weight, percent body fat after delivery. However, significant correlations were found between maternal serum leptin levels with their body weight, BMI, percent body fat at 16 weeks after delivery ( r = 0.80, p < 0.01; r = 0.90, p < 0.001; r = 0.83, p < 0.01, respectively) . There were no cor-relations between the infant's serum leptin levels and their weight, height, head circumference, and chest circumference. No significant relations were also found between maternal serum leptin levels with those of their infants. As a conclusion, maternal serum levels of leptin should be used with a caution to estimate their infant's leptin levels as well as their anthro-pometric parameters. Further researches are needed to examine the relationship among the leptin levels of mother's serum, breast milk, placenta, and infant's serum.