FOR: Fertility preservation for women with ovarian endometriosis: It is time to adopt it as routine practice

Fertility preservation techniques are widely accepted as standard of care for women undergoing treatment for cancer who are at risk of premature ovarian insufficiency. The same approach is not yet well established in benign conditions. There is ample evidence that women who have endometriosis are twice as likely to experience infertility in the future (Prescott et al. Hum Reprod 2016;31:1475– 82). Ovarian endometriomas reduce the ovarian reserve by exposing healthy ovarian tissue to the pathological process of endometriosis and to mechanical stretch, resulting in a progressive reduction in the pool of primordial follicles. Surgery to treat ovarian endometriomas further reduces ovarian reserve through loss of normal ovarian tissue during cystectomy and ablation. Following surgical removal, there is a reduction in ovarian reserve, as measured by antimüllerian hormone levels, by 30% in unilateral and 44% in bilateral endometriomas (Raffi et al. J Clin Endocrinol Metab 2012;97:3146– 54). The risk of premature ovarian insufficiency after bilateral ovarian endometrioma removal is 2.4% (Busacca et al. Am J Obstet Gynecol 2006;195:421– 5). Younger women have a higher recurrence rate of endometriomas requiring repeat surgery, which compounds the insult to their ovarian reserve. Accepting this risk, the European Society for Gynaecological Endoscopy, the European Society for Human Reproduction and Embryology and the World Endometriosis Society have collaborated in developing recommendations on the practical aspects of endometrioma surgery to reduce its adverse impact. Women with endometriosis are often subjected to the pressure of early childbearing based on their risk of infertility, whereas there is a societal trend towards delaying parenthood. Success rates of in vitro fertilisation are dependent on oocyte yield. The number of oocytes retrieved from women with endometriomas undergoing ovarian stimulation is substantially reduced, particularly in the presence of large and bilateral endometriomas (Kim et al. Reprod Biomed Online 2020;40:827– 34). It is, however, possible to restore cumulative livebirth rates in women with endometriosis when an equivalent number of oocytes is retrieved (Cobo et al. Reprod Biomed Online 2021;42:725– 32). There is evidence that almost half of women who undergo oocyte cryopreservation because of endometriosis subsequently use their oocytes, highlighting substantial utilisation of stored gametes within this group of women (Cobo et al. Fertil Steril 2020;113:836– 44). In light of this information, it is difficult to justify excluding women with endometriosis from having fertility preservation. A structured approach is required to grade the risk to fertility in endometriosis rather than questioning the validity of fertility preservation in these women. For the construction of criteria for offering fertility preservation, prospective data collection is required to understand longterm fertility patterns. Size of endometrioma, bilaterality, previous surgery and age are the obvious candidates in determining risk. An early discussion around reproductive planning is essential in women with ovarian endometriosis regarding the implications of their significant risk of diminished ovarian reserve and premature ovarian insufficiency. Oocyte and embryo cryopreservation offer women with ovarian endometriosis an effective and reliable option to increase their chance of reproductive success, particularly in young women with large or bilateral endometriomas who may require surgical intervention, those who have had previous surgery and those who are not in a position to embark upon pregnancy. It is imperative that the risk to ovarian reserve and fertility as well as the role of fertility preservation are Accepted: 5 August 2021 | Published Online 17 April 2022