THE ASSOCIATION OF AMH WITH ENDOMETRIAL THICKNESS IN GONADOTROPIN STIMULATION/INTRAUTERINE INSEMINATION CYCLES

Abstract

The role of anti-Müllerian hormone (AMH) and its receptor (AMH-R) on endometrial function and development is not well known. However, endometrial production of AMH has been reported, and endometrial expression of both AMH and AMH-R has shown cyclic variation with unclear significance. Our objective was to evaluate the association, if any, between AMH and pre-ovulatory endometrial thickness (ET) in gonadotropin induction (Gn)/intrauterine insemination (IUI) cycles. Retrospective cohort study. All Gn/IUI cycles (n=11,383) taking place at a large academic fertility center between 11/2007 and 12/2019, were retrospectively reviewed. 1,856 Gn/IUI cycles (from 912 patients) with a recorded pre-treatment serum AMH level and information available on endometrial thickness (ET) (measured by transvaginal ultrasound on either the day of or the day prior to HCG-trigger) were identified and included in the current analysis. Uterine factor infertility patients were excluded. Statistical analysis: Parametric and non-parametric tests were used as appropriate. Linear regression models, adjusted for potential confounders, were used to evaluate the effect of AMH on ET (bAMH stands for the regression coefficient of AMH). P < 0.05 was considered significant. Mean (SD) age, BMI, and AMH were: 35.9 (4.0) years, 25.1 (5.1) kg/m2, and 3.5 (4.2) ng/ml, respectively. Idiopathic infertility was the most common diagnosis (32.0%), and PCOS accounted for 8.7% of the population. Mean (SD) and median (IQR) ET (mm) were: 9.1 (2.3) and 9.0 (7.5, 10.4), respectively, when measured on HCG-trigger day, and 8.4 (2.3) and 8.0 (7.0, 10.0), respectively, when measured the day prior to it. Unadjusted regression models, showed a positive, albeit weak, correlation between AMH and ET (as measured on both HCG-trigger day and day prior to it) [r: 0.1, bAMH (95%CI): 0.03 (-0.003, 0.06), p: 0.08, and r: 0.1, bAMH (95%CI): 0.04 (0.01, 0.08), p: 0.02, respectively]. When models were adjusted for BMI, prior parity, and peak estradiol (E2) levels, the positive correlation between AMH and ET became stronger, [r: 0.2, bAMH (95%CI): 0.04 (0.03, 0.11), p: 0.009; r: 0.3, bAMH (95%CI): 0.07 (0.03, 0.11), p<0.001, for HCG-trigger day and day prior to HCG, respectively]. When models were further adjusted for PCOs diagnosis, the results remained significant [r: 0.2, bAMH (95%CI): 0.04 (0.001, 0.08), p: 0.045; r: 0.3, bAMH (95%CI): 0.05 (0.01, 0.10), p:0.03; for HCG-trigger day and day prior to HCG, respectively]. Pre-treatment, circulating serum AMH levels correlated positively with endometrial thickness in the pre-ovulatory phase of Gn/IUI cycles. Our data suggests a possible independent effect of AMH on endometrial development among patients undergoing Gn/IUI treatments.