Onset of ovulation after menarche in girls: a longitudinal study.

Introduction: Hypothalamic-pituitary axis maturity has been believed to be the rate-limiting step in the development of ovulatory menstrual cycles. We hypothesized that, given current nutritional conditions, hypothalamic-pituitary axis maturation would be relatively rapid in menarcheal girls.

Methods: Daily urine and menstrual records were collected for 2 yr each from 10 girls aged 11-13 yr at study entry.