Anti-Müllerian hormone decreased in women with superficial peritoneal endometriosis and associated with an elevated inflammatory profile

Abstract: Endometriosis is a common, inflammatory condition impacting 200 million women and those assigned female at birth, where 25-40% experience infertility. Ovarian endometriosis is known to decrease anti-Müllerian hormone (AMH) levels and contribute to infertility, but little is known about how the most common subtype, superficial peritoneal endometriosis (SPE), might play a role. Venous blood samples (n = 105) and pelvic peritoneal fluid (n = 38) were collected from women with suspected endometriosis at the time of diagnostic laparoscopy. AMH and inflammatory cytokine levels were measured by ELISA or Luminex. Women were classified by surgical findings as no endometriosis observed (control; n = 39), superficial peritoneal lesions only (SPE; n = 43), or SPE with ovarian endometriosis (SPE + OE; n = 23). Women were further grouped by their use of hormone treatments to manage endometriosis symptoms. SPE + OE women were older than SPE (P = 0.04) and control (P = 0.02). Serum AMH was lower for SPE (P = 0.009) and SPE + OE women (P = 0.002) compared to control when accounting for age. Elevated serum IL-17 (P = 0.02), TNF-α (P = 0.03), and peritoneal fluid IL-23 (P = 0.004) were observed for SPE compared to control (P = 0.03). These differences were specific to women not using hormones. Women with SPE, with or without OE, have lower AMH - indicative of reduced ovarian reserve - compared to control. For SPE, diminished AMH was associated with compartment-specific and hormone-dependent elevated inflammatory profiles in the serum and peritoneal fluid. Our data support the need for further investigation into inflammation as a mechanism underlying reduced ovarian reserve in women with SPE. Lay summary: Endometriosis is a common condition that impacts one in ten women, up to half of whom also experience infertility. The endometriosis fertility index and levels of anti-Müllerian hormone (made by the ovaries) in the blood can provide insight into fertility potential for women with endometriosis; however, neither have been well used to investigate how the most common type of endometriosis (SPE) affects fertility. This accounts for 80% of cases, and here for the first time, we show that the endometriosis fertility index and levels of anti-Müllerian hormone are lower for women with superficial endometriosis. We also investigated levels of inflammation in the blood and pelvic cavity and found increased levels of inflammation for women with SPE. These results demonstrate increased inflammation is present when anti-Müllerian hormone is reduced, suggesting that inflammation may contribute to infertility in women with endometriosis.