Size at birth predicts age at menarche.

Area of Science:

• Human Biology
• Developmental Biology
• Reproductive Health

Background:

• The prenatal environment's role in determining later disease risk is a subject of ongoing scientific debate.
• Intrauterine growth, encompassing size and maturity at birth, is being investigated for its long-term health implications.
• Understanding factors influencing pubertal maturation is crucial for assessing developmental trajectories.

Purpose of the Study:

• To examine the relationship between intrauterine growth (size and maturity at birth) and age at menarche.
• To identify other factors, including postnatal growth and socioeconomic status, that influence pubertal timing.
• To contribute to the understanding of fetal programming and its impact on later health.

Main Methods:

• Utilized data from the Cebu Longitudinal Health and Nutrition Survey, following a cohort of Filipino infants since birth.
• Employed Weibull parametric survival time models to analyze age at menarche in 997 girls aged 14-15.
• Assessed birth size (length, weight, gestational age), postnatal growth, body composition at 8 years, diet, socioeconomic status, and maternal characteristics.

Main Results:

• Median age at menarche was 13.1 years; earlier menarche was associated with urban residence and higher socioeconomic status.
• Girls who were long and thin at birth ( >49 cm, <3 kg) experienced menarche approximately 6 months earlier.
• Birth size effects on menarche were independent of later body composition, diet, and maternal factors.

Conclusions:

• Provides evidence for fetal programming, indicating that in utero development establishes future growth and maturation patterns.
• Highlights that rapid postnatal growth amplifies the effects of birth size on pubertal timing.
• Suggests that birth size and postnatal growth are independent predictors of earlier pubertal maturation.