BACKGROUND: Current data suggest that excessive androgen exposure can lead to 
the development of polycystic ovaries and polycystic ovary syndrome (PCOS). 
Anti-Müllerian hormone (AMH) levels reflect the number of small antral follicles 
in the ovaries and are elevated in PCOS. We hypothesized that protracted 
reduction of circulating androgens and/or insulin resistance would reduce 
circulating AMH concentrations in women with PCOS.
METHODS: A prospective, randomized, double-blind 26 week long study was 
undertaken in 50 women with PCOS. They all received diet and lifestyle 
counselling, and metformin 850 mg three times daily. Concomitantly, they were 
randomized to either dexamethasone 0.25 mg daily (n = 25) or placebo (n = 25). 
Thirty-eight women completed the study. AMH (primary outcome) and other hormone 
levels were measured at inclusion and after 8 and 26 weeks of treatment.
RESULTS: At baseline in univariate regression analyses, AMH levels associated 
positively with testosterone levels (P = 0.041) and ovarian volume (P = 0.002). 
In multivariate regression analyses, AMH associated positively with testosterone 
P = 0.004), and negatively with dehydroepiandrosterone sulphate (DHEAS) (P = 
0.001) and C-peptide levels (P = 0.020). Circulating AMH concentrations were 
unaffected by 6 months of lifestyle counselling with metformin and placebo 
treatment. AMH levels were also unaffected by 6 months of androgen suppression 
with dexamethasone in addition.
CONCLUSIONS: AMH levels in untreated PCOS women associated positively with 
testosterone, and negatively with DHEAS and C-peptide levels. Six months of 
androgen suppression by either metformin or low-dose dexamethasone treatment 
failed to influence circulating AMH levels.