Vasopressin helped surgeons control bleeding more quickly during laparoscopic removal of ovarian endometriomas, but it did not preserve ovarian reserve as measured by the blood marker AMH over the following year, a randomized trial found.
The result separates two questions about this operation. The drug appeared to make part of the procedure more efficient, while the study found no significant difference between vasopressin and standard surgery in the change in AMH from before the operation to 12 months later.
What the trial found
The study assigned 75 women with unilateral ovarian endometriomas to one of two groups: 37 received vasopressin during cyst removal and 38 underwent the same type of laparoscopic cystectomy without the injection. Eleven participants were later lost to follow-up or excluded, leaving 60 who completed the study per protocol.
In the vasopressin group, cyst stripping took an average of 8.9 minutes, compared with 14.4 minutes in the control group. That difference did not meet the study's threshold for statistical significance. The reported p-value for the comparison was .
The clearest operative difference came after the cyst was removed. Time to hemostasis, meaning control of bleeding, averaged 2.2 minutes with vasopressin and 6.5 minutes without it. The reported p-value was , and no endometrioma recurrence was observed during the 12-month follow-up.
No measurable AMH advantage
The trial's main outcome was the change in serum AMH from baseline to 12 months. AMH fell by an average of 0.96 ng/mL in the vasopressin group and 1.14 ng/mL in the control group. The difference was not statistically significant; the reported p-value was .
AMH declined soon after surgery and partly recovered at later follow-up, but the pattern over time was similar in both groups. The overall group-by-time comparison was not significant; the reported p-value was , and no individual follow-up point differed significantly between groups.
The findings were unchanged in analyses that grouped participants by their starting AMH level or adjusted for baseline AMH and endometrioma size. Analyses using a last-observation-carried-forward approach and the per-protocol population also matched the primary intention-to-treat result.
How the procedure was tested
This was a single-center, parallel-group randomized controlled trial focused on women with unilateral ovarian endometriomas. Randomization was stratified by baseline AMH and used computer-generated blocks of four, with the allocation sequence prepared by an independent statistician.
Before the cyst was enucleated, the vasopressin group received 20 IU diluted in 50 mL of saline, injected between the cyst wall and the ovarian cortex; 10 to 30 mL was administered. The control group had no vasopressin injection, and bleeding was managed with suturing and, when needed, bipolar coagulation.
The primary analysis included all randomized participants; additional analyses examined the participants who completed the protocol. The researchers also used statistical models that accounted for baseline AMH and cyst size and tracked AMH measurements over time.
What the result does and does not show
The authors concluded that vasopressin improved surgical efficiency but did not reduce the postoperative decline in AMH. Their interpretation was that reducing bleeding and exposure to bipolar coagulation alone may not be enough to preserve ovarian reserve.
The absence of a statistically significant difference does not prove that vasopressin and standard surgery are equivalent. The loss of 11 participants reduced the per-protocol sample, so the result cannot rule out a modest effect.
The trial also followed participants for only 12 months and did not measure spontaneous conception, assisted-reproduction outcomes or live birth. Because bleeding control involved both suturing and selective bipolar coagulation, that combination may have reduced the chance of seeing an ovarian-sparing effect from vasopressin alone.
The next question is fertility
The evidence directly applies to the selected unilateral-endometrioma population treated at one center, not to every person undergoing endometrioma surgery. The study measured AMH, operative times, recurrence and tissue findings, but it did not establish whether vasopressin changes longer-term fertility outcomes.
Pathology likewise found no significant difference between groups in cyst-wall thickness, attached ovarian-tissue thickness or the proportion of excised tissue associated with the ovarian specimen. Those tissue measures, like AMH, do not answer whether the procedure changes conception or live-birth outcomes.
The research was supported by a Faculty Research Grant from Yonsei University College of Medicine, with grant numbers 6-2022-0065 and 6-2026-0097.
Paper data and sources
Original title: Impact of vasopressin-assisted laparoscopic endometrioma excision on ovarian reserve: a randomized controlled trial
Authors: Lee J, Park E, Park H et al.
Journal/Repository: Frontiers in reproductive health
Status: Peer-reviewed
First online: 2026-10-19
DOI: Not available
Original paper · Full text