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

Objective: 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.

Methods: 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.

Results: 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/m or more (percent difference: -44.0 % (-63.7, -13.8)), compared to those with a body mass index of under 25 kg/m (percent difference: -19.8 % (-41.7, 10.4)), but did not vary by parity or infertility history.

Conclusions: 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.