Birth weight, early weight gain and pubertal maturation: a longitudinal study.

OBJECTIVE

To investigate the effect of birth weight and early weight gain on the timing of various measures of puberty in both girls and boys.

METHODS

A total of 856 newborns enrolled in the North Carolina Infant Feeding Study were followed to age 5 years, with 600 children followed up at adolescence. Birth weight was obtained from medical records and children were weighed at study visits until age 5 years; gains in standardized weights were calculated over four early age intervals: 0-6 months, 6-12 months, 1-2 years and 2-5 years. Age at menarche in girls and age at advanced Tanner stages in both girls and boys were reported by adolescents and their parents. Survival models were used to analyse the effects of birth weight and early weight gain on these outcomes.

RESULTS

Girls with higher birth weight and greater weight gains during the four early age intervals were younger when they reached menarche and advanced Tanner stages; boys with greater early weight gains also were younger when they reached advanced Tanner stages, but few of these effects were statistically significant.

CONCLUSIONS

Higher birth weights and greater weight gains during infancy and early childhood can lead to earlier sexual maturation in girls.