CONTEXT: The majority of Turner syndrome (TS) patients suffer from accelerated loss of primordial follicles. Low circulating levels of anti-Müllerian hormone (AMH) may predict the lack of spontaneous puberty in prepubertal girls and imminent premature ovarian insufficiency (POI) in TS women with preserved ovarian function.

OBJECTIVES: To evaluate the association between circulating AMH and ovarian status in TS patients.

DESIGN: Longitudinal observational cohort study.

SETTING: Tertiary referral center for pediatric and gynecologic endocrinology.

PARTICIPANTS: A total of 120 TS patients, aged 0 to 48 years.

MAIN OUTCOME MEASURES: Longitudinal measurements of AMH, FSH, LH, estradiol, and inhibin B according to age, karyotype (45,X; 45,X/46,XX mosaicism; miscellaneous karyotypes), and ovarian status (group 0, prepubertal; group 1, never ovarian function; group 2, ongoing ovarian function; and group 3, loss of ovarian function).

RESULTS: Ovarian status was highly associated with the TS karyotype: spontaneous puberty—45,X (three of 44 patients), 45,X/46,XX (15 of 17), miscellaneous (17 of 42); and POI—45,X (three of three), 45,X/46,XX (one of 15), and miscellaneous (eight of 17). AMH was associated with ovarian status (eg, group 1, <2 pmol/L; vs group 2, 19 pmol/L; P < .001). AMH < 4 pmol/L (corresponding to <-2 SD) predicted absent puberty in prepubertal girls and POI in adolescent and adult patients.

CONCLUSION: The majority of women with mosaic karyotype 45,X/46,XX had ongoing ovarian function in early adulthood. AMH < -2 SD predicted failure to enter puberty in young TS girls and imminent POI in adolescent and adult TS patients.