Beyond anti-Müllerian hormone or antral follicle count alone: anti-Müllerian hormone and antral follicle count ratio as marker of ovarian responsiveness to gonadotrophins.

RESEARCH QUESTION: Is the anti-Müllerian hormone to antral follicle count ratio (AMH‒AFC) associated with ovarian responsiveness to gonadotrophins during ovarian stimulation? DESIGN: Retrospective cohort study including 2162 IVF and intracytoplasmic sperm injection ovarian stimulation cycles carried out using a gonadotrophin releasing hormone antagonist protocol at a tertiary IVF centre. Associations between the AMH‒AFC ratio and ovarian responsiveness were evaluated with multiple regression analysis using the follicular output rate (FOR), follicle-to-oocyte index (FOI) and oocytes retrieved. RESULTS: The AMH‒AFC ratio showed significant positive correlation with both FOI (r = 0.62, 95% CI 0.59 to 0.65) and FOR (r = 0.62, 95% CI 0.59 to 0.65; both P < 0.001), with stronger associations than AMH or AFC when assessed individually. When stratified by AMH‒AFC quartiles, a progressive increase was observed in pre-ovulatory follicles, retrieved oocytes, metaphase II oocytes, FOI and FOR across higher ratio categories. In multivariable analyses adjusted for age, body mass index and gonadotrophin dose, the AMH‒AFC ratio explained a greater proportion of variance in FOI and FOR than either marker alone. The combined use of AMH and AFC, however, remained superior for predicting absolute oocyte and metaphase II yield. CONCLUSIONS: The AMH‒AFC ratio is associated with dynamic markers of ovarian responsiveness during ovarian stimulation and may provide complementary information regarding follicular sensitivity to gonadotrophins. Although it does not replace the combined use of AMH and AFC for predicting absolute oocyte yield, the ratio may help identify women with discordant ovarian reserve profiles who are at risk of suboptimal ovarian response despite apparently reassuring follicle counts.