Gender differences in neonatal subcutaneous fat store in late gestation in relation to maternal weight gain

Objective: To study gender differences in fat store in human newborns and their relation to duration of gestation and maternal weight gain. Methods: The ratios subscapular skinfold thickness boy weight (SST BW) and tricipital skinfold thickness body freight (TST BW) were calculated in a sample of 13 609 premature and term neonates from the maternity hospital of Clamart. Hauts-de-Seine, France. Results: Whereas BW, SST and TST increased with gestational age. SST BW and TST BW ratios decreased regularly, in males is in females. This result reflects a progressive reduction of subcutaneous fat store per body weight unit as the duration of gestation increases. Male, had smaller values of SST, BW and TST, BW ratios than females whatever the gestational age. Increasing maternal freight gain during the third gestational trimester did not improve the subcutaneous fatness per body weight unit of the newborn. Earlier amount of maternal weight gain had all effect oil the TST BW index exclusively in females. Conclusions: In newborns, a gender difference was observed in the ratio of subcutaneous fat per unit of body weight: this ratio is lower in male, than in females. This result argues for it gender difference in mobilization of fat store to ensure normal growth in the last weeks of pregnancy: males lose more fat but gain more weight than females in this period. Late maternal weight gain does not affect the proportion of subcutaneous fatness by body weight unit in both genders.