Prospective assessment of the impact of endometriomas and their removal on ovarian reserve and determinants of the rate of decline in ovarian reserve

STUDY QUESTION: Do the presence of endometriomas and their laparoscopic excision lead to a decrease in ovarian reserve as assessed by serum anti-Müllerian hormone (AMH) levels? SUMMARY ANSWER: Both the presence and excision of endometriomas cause a significant decrease in serum AMH levels, which is sustained 6 months after surgery. WHAT IS KNOWN ALREADY: No previous comparison of serum AMH levels between women with and without endometrioma has been reported. However, studies have suggested a decline in serum AMH levels 1-3 months after endometrioma excision but long-term data are needed. STUDY DESIGN, SIZE, DURATION: A prospective cohort study including 30 women with endometrioma >2 cm were age matched with 30 healthy women without ovarian cysts. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women with endometrioma underwent laparoscopic excision with the stripping technique. Serum AMH level and antral follicle count (AFC) were determined preoperatively, 1 and 6 months after surgery. Correlation analyses were undertaken in order to identify determinants of surgery-related change in ovarian reserve. MAIN RESULTS AND THE ROLE OF CHANCE: Compared with controls at baseline, women with endometrioma had lower AMH levels (4.2 ± 2.3 versus 2.8 ± 2.2 ng/ml, respectively, P = 0.02) and AFC (14.7 ± 4.1 versus 9.7 ± 4.8, respectively, P < 0.01). Serum AMH levels were further decreased 6 months after surgery (2.8 ± 2.2 versus 1.8 ± 1.3 ng/ml, P = 0.02), while AFC remained unchanged (9.7 ± 4.8 versus 10.4 ± 4.2, P = 0.63). The rate of decline in AMH was not correlated with age, laterality of endometrioma, cyst diameter or the number of primordial follicles on the surgical specimens. The preoperative serum AMH level was positively correlated with the rate of decline in serum AMH after surgery (r = 0.47, P = 0.02). LIMITATIONS, REASONS FOR CAUTION: The absence of a non-treated group of women with endometriomas as a further control prevents comment on the presence of a progressive decline in ovarian reserve related to endometrioma per se. The sample size may be too small for detection of factors correlated with the extent of ovarian damage. WIDER IMPLICATIONS OF THE FINDINGS: While the findings are mostly in agreement with previous studies, the present study is the first to show that the presence of endometrioma per se is associated with a decrease in ovarian reserve. The extent of surgery-related decline in ovarian reserve is not predictable using preoperative or perioperative factors. It may be prudent to measure AMH levels preoperatively and delay/avoid surgical excision as far as is possible if subsequent fertility is a concern. Additional studies are required to further investigate whether the endometrioma-related decline in ovarian reserve per se is progressive in nature and whether it exceeds the surgery-related decline. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by the Research Fund of the Uludag University School of Medicine. The authors have no conflict of interest associated with this study.