Peripubertal changes in circulating antimüllerian hormone levels in girls

ObjectiveTo identify correlates and longitudinal changes in circulating antimüllerian hormone (AMH) levels as a marker of ovarian primordial follicle recruitment in normal peripubertal girls.DesignObservational study using mixed longitudinal and cross-sectional analyses.SettingNot applicable.Patient(s)Unselected girls assessed at ages 7–11 years.Intervention(s)None.Main Outcome Measure(s)AMH, inhibin B, and FSH levels were analyzed in blood samples collected at ages 7, 9, and 11 years for longitudinal analyses and at age 8 years for cross-sectional analyses.Result(s)In the cross-sectional analysis, AMH levels at age 8 years were lower in pubertal girls (median 25.0 pmol/L, interquartile range [IQR] 16.0–33.9; n = 39) than in prepubertal girls (33.5 pmol/L, IQR 22.3–49.1; n = 342). In prepubertal girls, higher AMH levels were associated with higher inhibin B levels, lower FSH levels, and larger body mass index at age 8 years and subsequently with later age at menarche. AMH levels were unrelated to birth weight or birth length. In the longitudinal analysis, AMH levels increased between ages 7 (median 27.0 pmol/L, IQR 19.2–34) and 9 years (32.0 pmol/L, IQR 26.5–42.7), then declined between 9 and 11 years (26.5 pmol/L, IQR 19–42.25) with high intraindividual correlation in AMH levels between ages 7 and 9 years and 7 and 11 years.Conclusion(s)Measurement of circulating AMH and inhibin B levels suggests that the rate of ovarian primordial follicle recruitment increases in the prepubertal years then declines again following the onset of puberty as follicular activity pattern changes