Diminished ovarian reserve is found in 6% of women under 25 years old with a known or unknown etiology.1 According to the European Society of Human Reproduction and Embryology consensus, an antral follicle count of fewer than 5-7 follicles and anti-Müllerian hormone (AMH) levels below 0.5-1.1 ng/mL are the 2 most relevant criteria for diminished ovarian reserve.2., 3., 4. A low AMH level in adult women is a reliable risk factor for early menopause or primary ovarian insufficiency.5., 6., 7. However, knowledge of the natural history and clinical significance of low serum AMH levels in female adolescents is still very limited.

Several studies have reported a reference value for serum AMH levels from birth to adulthood.8., 9., 10. In healthy females, the serum AMH concentration is exceptionally low at birth and gradually increases during infancy and childhood, reaching the highest level during childhood and puberty.10 The maximum AMH level continues until the mid-20s and thereafter decreases with age to undetectable levels at menopause. The overall features of age-specific distribution have been constantly reported; nonetheless, the age at which the AMH level peaks has been reported to vary from 8 years old to the late teens.8., 9., 10., 11. For this reason, it remains unknown whether low AMH levels in teenagers normalize with age or whether low AMH levels continue to remain low, leading to serious deficiencies in ovarian function.

The aim of the present study was to elucidate the longitudinal changes in low serum AMH levels in female adolescents and to identify predictive factors for spontaneous improvement.