Laparoscopically confirmed endometriosis and anti-Müllerian hormone levels: Findings from the Nurses' Health Study II

•Women with a history of laparoscopically confirmed endometriosis had30 % lower levels of anti-Müllerian hormone (AMH) than women without endometriosis.•Among women with a body mass index of 25 kg/m2 or more, women with endometriosis had 44 % lower levels of anti-Müllerian hormone.•Lower levels of anti-Müllerian hormone in women with endometriosis may be one mechanism through which endometriosis influences risk of infertility, younger age at menopause, and cardiovascular disease. Anti-Müllerian hormone is a reliable measure of ovarian reserve associated with menopause timing and fertility. Previous studies have observed that individuals with endometriosis have lower anti-Müllerian hormone levels than those without. However, sample sizes have been small and information is limited regarding the long-term influence of endometriosis on anti-Müllerian hormone levels among the general population, which may have important implications for menopause timing and chronic disease risk. Among 1961 premenopausal women in the Nurses' Health Study II who provided a blood sample and had not been pregnant in the last 6 months, we used generalized linear models to determine the association between laparoscopically-confirmed endometriosis and log-transformed plasma anti-Müllerian hormone level, adjusted for age (continuous and squared) and other potential confounding variables. Participants were on average 40 years old (interquartile range 37–42 years) at blood draw. Women with endometriosis diagnosed prior to blood draw (n = 119) had a lower mean anti-Müllerian hormone level (1.6 ng/mL [SD = 2.3]) than women without known endometriosis (n = 1842) (2.8 ng/mL [SD = 3.0]). In multivariable adjusted models, women with endometriosis had 29.6 % lower anti-Müllerian hormone levels (95 % CI: −45.4, −9.2 %) than women without. This association was greater among women with a body mass index of 25 kg/m2 or more (percent difference: −44.0 % (−63.7, −13.8)), compared to those with a body mass index of under 25 kg/m2 (percent difference: −19.8 % (−41.7, 10.4)), but did not vary by parity or infertility history. Lower anti-Müllerian hormone levels in women with endometriosis may be one mechanism through which endometriosis influences risk of infertility, younger age at menopause, and cardiovascular disease.