Association Between Body Mass Index and Anti-Müllerian Hormone in Women With Ovarian Endometrioma and Dermoid Cyst

Yunjeong ParkHyemin ParkInha LeeJae Hoon LeeSiHyun ChoYOUNG SIK CHOI^*

• Yonsei University College of Medicine, Seodaemun-gu, Republic of Korea

Background Adiposity influences reproductive function via endocrine and immune pathways. The association between body mass index (BMI) and anti‑Müllerian hormone (AMH) in endometriosis is uncertain, and BMI may not fully capture adiposity‑related biology relevant to ovarian reserve. We assessed whether BMI is associated with AMH in untreated ovarian endometrioma and whether this differs from dermoid cysts. Methods Retrospective single‑center cohort of 951 newly diagnosed, reproductive‑age women from January 1, 2020 to December 31, 2023 (717 endometrioma; 234 dermoid). AMH was measured on one platform; imaging included transvaginal ultrasonography with MRI or contrast‑enhanced abdominopelvic CT as needed. Multivariable linear regression modeled log‑AMH versus BMI, adjusting for age, diagnosis, cyst size and laterality, parity, smoking, alcohol use, cycle regularity, and cycle length. Nonlinearity was screened with restricted cubic splines; piecewise models explored age breakpoints. An interaction term tested whether the BMI effect differed by diagnosis. Effects are reported as percent change in AMH per 1 kg/m². Results Women with endometrioma were older (31.9 vs 29.9 years; P<.001) and had lower BMI (21.1 vs 22.4 kg/m²; P<.001) than those with dermoid. Median AMH was 2.52 vs 2.70 ng/mL; age‑adjusted geometric means did not differ (P=.245). Piecewise modeling identified earlier age breakpoints in endometrioma (35.7 years) than dermoid (40.4 years). In fully adjusted models, each 1 kg/m² higher BMI was associated with 2.3% lower AMH (P=.003). Group‑specific estimates were −1.9% per kg/m² in endometrioma (P=.060) and −2.8% per kg/m² in dermoid (P=.009); the BMI×diagnosis interaction was not significant (P=.538). Model fit was modest (adjusted R²=0.22), and BMI explained 1% of AMH variance (partial R²=0.01). Sensitivity analyses restricting the BMI range yielded consistent directions of effect with attenuation at lower BMI. Conclusions Across endometrioma and dermoid cysts, BMI shows a weak inverse association with AMH without evidence of between‑group differences. Given BMI’s minimal explanatory value, local ovarian factors may more strongly determine ovarian reserve in endometrioma. Limited numbers of obese participants constrain inference at higher BMI; studies with broader BMI distributions and integrated metabolic profiling are warranted.