Blood samples were collected before surgery and on the third day after surgery to determine the serum AMH levels from all study participants following the guidelines of the Declaration of Helsinki. The serum AMH level was measured using a commercially available enzyme-linked immunosorbent assay kit (AMH Gen II assay; Beckman Coulter, Inc.), and the lowest detection limit of the kit was 0.08 ng/mL with both the intra- and interassay coefficients of variation below 8.0% [8 (link)16 (link)].
The rate of decline in AMH levels was calculated using the following formula [8 (link)16 (link)]:
(preoperative AMH level – postoperative Day 3 AMH level)/(preoperative AMH levels) × 100 (%).