Role of Prenatal Characteristics and Early Growth on Pubertal Attainment of British Girls WHAT'S KNOWN ON THIS SUBJECT: Rapid growth during infancy and childhood obesity predict earlier puberty attainment. WHAT THIS STUDY ADDS: Many of the prenatal factors studied and weight and BMI gain during infancy seemed to exert comparable influences in the ages of breast, pubic hair, and menarche attainment assessed in the same girls.

The objective of this study was to explore the influence of maternal prenatal characteristics and behaviors and of weight and BMI gain during early childhood on the timing of various puberty out- comes in girls who were enrolled in the Avon Longitudinal Study of Parents and Children. METHODS: Repeated self-assessments of pubertal development were obtained from 4000 girls between the ages of 8 and 14. Data on prenatal characteristics and weight at birth and 2, 9, and 20 months of age were obtained from questionnaires, birth records, and clinic visits. Infants' weights were converted to weight-for-age and BMI SD scores (SDSs; z scores), and change values were obtained for the 0- to 20- month and other intervals within that age range. We used parametric survival models to estimate associations with age of entry into Tanner stages of breast and pubic hair and menarche. RESULTS: Maternal initiation of menarche at age12, smoking during pregnancy, and primiparity were associated with earlier puberty. A 1-unit increase in the weight SDS change values for the 0- to 20-month age interval was associated with earlier ages of entry into pubertal outcomes (0.19 - 0.31 years). Increases in the BMI SDS change values were also associated with earlier entry into pubertal outcomes (0.07- 0.11 years). CONCLUSIONS: Many of the maternal prenatal characteristics and weight and BMI gain during infancy seemed to have similar influences across different puberty outcomes. Either such early factors have com- parable influences on each of the hormonal processes involved in puberty, or processes are linked and awakening of 1 aspect triggers the others. Pediatrics 2010;126:e591-e600