BACKGROUND: Anti-Müllerian hormone (AMH) is secreted by granulosa cells of 
ovarian early developing follicles and its serum levels have been shown to 
correlate with small antral follicle number. Since the pronounced androgen 
secretion from follicles/stroma in women with polycystic ovary syndrome (PCOS) 
remains until late reproductive age, and since AMH reflects the number of antral 
follicles, it was of interest to study the possible age-related relationship 
between AMH, androgens and follicle number in women with PCOS and in control 
women. Moreover, the possible effect of metformin on serum AMH levels and the 
relationship to follicle count and volume were studied.
METHODS: Forty-four healthy women (aged 21-44 years) and 65 women with 
previously diagnosed PCOS (aged 16-44 years) participated in the study. Serum 
basal AMH levels were correlated with those of serum androstenedione, 
testosterone, estradiol (E2), LH, FSH and inhibin B, and with follicle number. 
The effect of metformin on serum AMH concentrations, follicle number and ovarian 
volume was studied in 26 women (aged 20-41 years) with PCOS after 6 months of 
treatment.
RESULTS: Serum AMH levels were 2- to 3- fold higher in PCOS women than in 
healthy women. In control women, serum AMH levels correlated positively with 
those of serum androstenedione (r = 0.564, P < 0.001) and testosterone (r = 
0.328, P = 0.036) and negatively with serum FSH concentrations (r = -0.374, P = 
0.012) and age (r = -0.691, P<0.001). In women with PCOS, serum AMH levels 
correlated positively with those of androstenedione (r = 0.311, P = 0.011) and 
testosterone (r = 0.310, P = 0.011) and with follicle count (r = 0.352, P = 
0.012), and negatively with age (r = -0.300, P = 0.014). Serum AMH levels, the 
number of antral follicles and ovarian volume decreased significantly during 
metfromin treatment.
CONCLUSIONS: Serum AMH levels decreased with age both in healthy women and in 
women with PCOS, although they were always 2- to 3-fold higher and remained 
elevated until 40 years of age in PCOS subjects. Thus, since serum AMH levels 
correlate well with antral follicle count and serum androgen levels, the 
measurement of AMH could be used as a tool to assess ovarian ageing, to diagnose 
polycystic ovaries/PCOS and to evaluate treatment efficacy.