The post-operative decline in serum anti-Mullerian hormone correlates with the bilaterality and severity of endometriosis

BACKGROUND: To assess the impact of ovarian cystectomy for endometriomas on the ovarian reserve, we evaluated the pre- and post-operative levels of serum anti-Mullerian hormone (AMH). We also analyzed the correlations between factors related to endometriosis and surgery for endometriomas and the serum AMH levels to investigate which factors affect ovarian reserve. METHODS: Thirty-eight patients who were undergoing ovarian cystectomy for unilateral endometrioma (n = 20) and bilateral endometriomas (n = 18) participated. Preoperative and post-operative serum samples were collected and assayed for AMH levels, and changes between the two samples were analyzed in association with parameters of endometriosis and surgery for endometriomas. RESULTS: The mean AMH level was 3.9 ng/ml prior to surgery, and was reduced to 2.1 ng/ml at 1 month post-surgery. The rate of decline of the serum AMH level was significantly higher in the bilateral group than the unilateral group (62.8 +/- 29.6 versus 24.7 +/- 32.5%, P < 0.001). The rate of decline in the serum AMH levels showed a significant correlation to the revised American Society for Reproductive Medicine (rASRM) score (P = 0.003), but not age, cyst diameter, blood loss during the operation or the number of follicles removed in the specimens. CONCLUSIONS: Our results suggest that the decrease in ovarian reserve should be taken into account in patients indicated for cystectomy for bilateral endometriomas or unilateral endometrioma with high rASRM scores.