Ovarian Cystectomy Surgery Compromises Ovarian Reserve

By Eva Martin, MD of Elm Tree Medical, Inc.

Ovarian cysts are one of the most common diagnoses in the gynecologist’s office. From masses from endometriosis (endometriomas) to corpus luteum cysts (that can form when fluid gets trapped in a follicle after normal ovulation), many benign cysts require surgery if they are causing pain or causing the ovary to twist on itself and cut off blood supply. However, is the surgery to remove these cysts as benign as the cysts themselves? New research points to a decrease in fertility markers following benign ovarian cystectomy.

In the August 2016 Grey Journal, researchers from the United Kingdom published the results of a systematic review of ten articles studying 367 patients. The studies all measured the levels of Anti-Mullerian Hormone (AMH) following surgical excision of a benign ovarian cyst, excluding endometriomas. (The authors already published another review showing that AMH decreases after excision of endometriomas.)  Researchers have focused on AMH as the biomarker of choice for ovarian reserve, and by proxy, fertility, because it reflects the number of small antral follicles in the ovary and does not vary over the course of the menstrual cycle.

Most of the ten studies initially diagnosed the cysts via transvaginal ultrasound and confirmed the type of cyst on pathology after the surgery. The studies measured AMH before surgery and between one and six months post-operatively. Compiling the results of all ten studies, the researchers showed a significant decrease in AMH after surgery of 1.14 ng/ml, about a 38% drop. The fall in AMH was consistent for individual types of cysts, including dermoid cysts and cystadenomas. This decrease is also similar to the decrease seen after removal of endometriomas. The consistency across types of cysts suggests that the decrease in AMH may be due to the surgery, not the cyst itself.

One explanation for the decrease in AMH is perhaps surgeons also remove normal ovarian tissue when they remove the cyst. Another possibility is that electro-cautery used to control bleeding during the surgery causes thermal damage to the follicles.

Is a drop of 1.14 ng/mL clinically significant? Does it actually impact fertility? The studies did not measure a woman’s fertility (for instance, time to conceive or number of subsequent pregnancies), so we cannot know for sure. The study authors believe the drop is important because AMH levels usually decrease by about 5% a year, so a 38% drop translates to quite a few years! However, this does not likely reflect an equivalent drop in fertility. Anti-Mullerian Hormone only measures small antral follicles, not the total number of follicles in reserve. It’s possible that surgery damages the small antral follicles, but the overall reserve is still intact.

Does AMH recover with time? Not within 3 months. Any longer than that, and it’s just a guess. It’s possible that the decline levels out and never recovers. Therefore, this new synthesis of data showing a decline in Anti-Mullerian Hormone should cause surgeons to add another bullet to their mental Pro-Con lists for performing ovarian cystectomies. It’s possible (but definitely not certain) that these surgeries could have a negative effect on fertility. We want to hear from you! Would you counsel patients about fertility loss before ovarian cystectomy based on this data? In other words, is the data strong enough to add this factor to your counseling?