Background: To investigate the dynamics of serum anti-Müllerian hormone (AMH) levels during the luteal phase of controlled ovarian hyperstimulation (COH) and its possible association with follicle development.
Methods: We prospectively studied 34 women undergoing COH with GnRH agonist and FSH. On the day of hCG (dhCG), serum AMH, estradiol (E2), progesterone and hCG levels were measured, and ovarian follicles were sorted into three size classes: <12, 12-15 and 16-22 mm. Hormonal measurements were repeated 4 days (hCG + 4) and 7 days (hCG + 7) after hCG.
Results: From dhCG to hCG + 4, we observed a decline in serum AMH levels (-64 +/- 3%; P < 0.0001), which paralleled that of E2 levels. From hCG + 4 to hCG + 7, an increase in AMH levels occurred (82 +/- 28%; P < 0.02), whose magnitude was correlated with the number of < 12 mm follicles (r = 0.68; P < 0.0001) but not with other follicle size classes nor with the remaining hormone levels.
Conclusions: After hCG, AMH levels initially decline, presumably as an effect of follicle luteinization, then increase during the mid-luteal phase. Although the mechanisms implicated in the mid-luteal AMH increase are unclear, its positive association with small follicle count, but not with luteal progesterone and E2 levels, supports the hypothesis that AMH levels might reflect luteal follicle development.