Objective: To investigate the process of puberty development of healthy adolescent girls in Northern China.
Methods: 288 adolescent girls of Daqing city, Heilongjiang province, aged 5 to 16, were studied and followed up yearly for four years. The height, weight, fat percentage, second sex characteristics, and the blood levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E(2)) were examined.
Results: The mean age of puberty onset of these healthy adolescent girls was 8.5 years +/- 1.1 years. The blood levels of FSH, LH and E(2) were 0.2 mIU/L, 1.1 mIU/L and 0.06 nmol/L respectively (the 95 percentiles were 2.5 mIU/L, 2.3 mIU/L and 0.12 nmol/L respectively). Their mean age of menarche was 12.4 years +/- 1.2 years. The mean age of breast development was 8.8 years +/- 1.1 years.
Conclusion: The girls in Northern China begin their puberty development at younger ages than reported before.