The Recovery of Serum AMH Levels after Conservative Surgery for Ovarian Endometriomas May Be due to the Transient Compensatory Follicular Activation of the Contralateral Ovary

Abstract Objectives: To clarify the factors and mechanisms that influence changes in serum anti-Müllerian hormone (AMH) levels after the fertility-sparing surgery for ovarian endometriomas. Materials and Methods: We examined women with ovarian endometrioma who underwent fertility-sparing surgery in our hospital retrospectively. We classified patients into preoperative serum AMH levels of 1.2–6.0 ng/mL (normal ovarian reserve [NOR] group, n = 40) and with AMH levels of <1.2 ng/mL (diminished ovarian reserve [DOR] group, n = 16). Laparoscopic fertility-sparing surgery for ovarian endometriomas performed by cystectomy and/or cyst wall ablation. Serum AMH level determination at the pre- and postoperative period up to 12 months. Results: In the NOR group, AMH levels transiently decreased at 1–3 months after surgery and recovered to the preoperative levels at 6–9 months after surgery. In the women with bilateral lesions, the immediate postoperative decline was greater than that of women with unilateral lesions, and there was no trend toward recovery. In the DOR group, there was also a trend of immediate postoperative decline followed by gradual recovery, but there was no statistically significant difference in the trend of change. In women with unilateral lesion and belong to the NOR group, there were several women in whom the serum AMH level apparently increased from the preoperative level. Conclusion: Changes in serum AMH levels after fertility sparing surgery for ovarian endometriomas differ depending on the presence or absence of preoperative ovarian hypofunction and whether the patient is unilateral or bilateral. The transient elevation of AMH levels in unilateral women may indicate a compensatory change in the contralateral ovary in response to surgical invasion. The mechanisms that affect AMH levels after the surgery for endometriomas should be validated in future studies.