Ovarian Endometrioma

Guidelines for Selection of Cases for Surgical Treatment or Expectant Management

Molly Carnahan; Jennifer Fedor; Ashok Agarwal; Sajal Gupta


Expert Rev of Obstet Gynecol. 2013;8(1):29-55. 

In This Article

Laparoscopic Cystectomy

Cystectomy, a conservative surgical procedure, is a controversial treatment for endometriomas due to the invasive nature of the surgery. The laparoscopic procedure strips the cyst wall – the portion of the cyst containing the endometrial tissue. The benefits of this procedure include decreased recurrence rates, increased chance of spontaneous pregnancy and significant reduction in pelvic pain. After one procedure, recurrence rates range from 9.6 to 45% (Table 5).[47–49] Another advantage of cystectomy is the increase in spontaneous pregnancy rates following surgery. Studies have reported a wide range in spontaneous pregnancy rates ranging from 14 to 54% (Table 6).[47,49] Kitajima et al., suggested that the increase in spontaneous pregnancy following cystectomy might be due to decreased ovarian inflammation, which can lower follicular density.[42] Women who are 35 years of age or younger are encouraged to wait 1 year before considering IVF. Women who are older than 35 years of age are encouraged to wait 6 months before attempting IVF.[29]

However, the main controversy associated with cystectomy is that it damages or removes healthy ovarian cortex and follicles, leading to a decrease in ovarian reserve following the procedure. The AFC and AMH seem to be most affected by cystectomy Table 3 & Table 7). In a meta-analysis comparing eight studies of ovarian endometrioma treatment, the patients who had either unilateral or bilateral cystectomy had significantly lower AMH levels following the surgery than before surgery (WMD: -1.13; 95% CI: -0.36 to -1.88) (Table 7).[50,51] Ovarian failure, a serious risk associated with cystectomy, has been reported after bilateral endometrioma cystectomy, with rates ranging from 2.3 to 3.03%.[37,52]

In addition to potentially removing healthy cortex, inflammation after surgery could further damage the cortex or decrease vascularization.[53,54] The damage caused by scar tissue may reduce the volume of the healthy ovary, and scar tissue may interfere with oocyte retrieval.[52] A recent study on laparoscopic ovarian cystectomy reported that inexperienced surgeons had significantly diminished outcomes compared with experienced surgeons.[55] However, Biacchiardi et al. found reduced ovarian reserve following cystectomy even when the procedure was performed by experienced surgeons.[56]

Bongioanni et al. performed a retrospective, case–control study to assess the effects of cystectomy on IVF outcomes. This study consisted of women with an endometrioma, women who had a cystectomy for an endometrioma and women with tubal factor infertility. The results showed that IVF pregnancy rates per cycle were not significantly different between any of the groups (Table 1). However, the prior cystectomy group did have a significantly reduced AFC compared with both groups and reduced ovarian sensitivity (Table 3). Ovarian sensitivity is defined as the ovarian response to FSH stimulation independent of administered FSH. Therefore, Bongioanni et al. concluded that ovarian endometriomas do not significantly decrease IVF pregnancy rates compared with tubal factor infertility, and surgical treatment for endometriomas does not improve IVF outcome but instead may negatively affect ovarian response.[20] As stated previously, Matsuzaki et al. believed that cystectomy does not improve pregnancy outcomes due to the oxidative stress from the endometrioma that remains in healthy tissue following surgery, which continues to negatively affect oocyte quality.[43] Therefore, cystectomy should be avoided in women who do not have time to undergo the surgery and subsequently wait 6 months to 1 year before trying to attempting IVF. It should also be avoided in women with an already reduced ovarian reserve.


Aspiration is a noninvasive option in which a transvaginal ultrasound identifies the location of a cyst. Needle aspiration is then used to remove the fluid by transvaginal access. There are three common risks associated with the procedure: recurrence, infections and adhesions.[57,58] A study by Zhu et al. consisting of infertile patients with ovarian endometriomas (Table 5) reported that cyst recurrence was high after the first procedure (91.5%), but after repeat aspiration (up to six separate procedures) only 5.4% of patients had recurrent cysts. The average number of treatments needed was 3.1 ± 2.3, and repeated aspirations took place on average 33 days after the prior procedure. The cumulative pregnancy rate after 2 years was 43.4%, with 73.2% of the women achieving pregnancy doing so within 7–18 months following surgery. Of the 56 women achieving pregnancy, 44 did so naturally and 12 used intrauterine insemination for either male factor or other cervical factor infertility (Table 6). None of the patients had infections following cyst aspiration or oocyte retrieval.[59] Overall, aspiration alone has traditionally been regarded as an ineffective treatment for endometriomas. However, repeating the procedure in recurrent endometriomas can be a less invasive alternative to surgery.

Laparoscopic Endometrial Ablation

Laparoscopic endometrial ablation is an invasive surgical procedure in which the cyst is drained and the cyst wall is destroyed by electrosurgical current or laser energy.[60]

The CO2 laser is considered as a tissue-sparing energy source that has a more controlled penetration than electrical energy sources.[61] Reported pregnancy rates and recurrence rates at 60 months are similar between cystectomy and CO2 laser ablation (Table 5 & Table 6).[48] After CO2 laser ablation, the number of retrieved follicles and mature oocytes in women undergoing IVF was similar to that of women with tubal factor infertility, suggesting that while CO2 laser ablation does not negatively affect IVF outcomes, it does not improve them (Table 4).[62]

In a retrospective study of infertile women with ovarian endometriomas, following potassium-titanyl-phosphate (KTP) laser ablation, 48.9% became pregnant spontaneously and 50% of the remaining patients who elected to undergo IVF successfully achieved pregnancy during the first cycle (Table 4 & Table 6). Cysts recurred in 24.4% of patients and KTP does not negatively affect ovarian reserve (Table 4).[63]

A plasma laser is similar to a CO2 laser in that it destroys the tissue without coagulum destruction. Plasma energy laser uses argon gas and is reported to have no risk of accidental intraoperative overshoots and metallic instrument reflection. In a retrospective study of unilateral endometriomas using plasma energy ablation compared with cystectomy, Roman et al. reported that plasma laser was a better treatment option because the procedure results in less reduction in ovarian volume and AFC than cystectomy (Table 3). However, spontaneous and IVF pregnancy rates were not reported for this study.[64] Currently, a prospective clinical trial is comparing the effects of plasma laser ablation and cystectomy for ovarian endometriomas on AFC following surgery.[201]

According to a Cochrane review, there is insufficient evidence in support of either cystectomy or ablation for IVF success (OR: 1.40; 95% CI: 0.47, 4.15).[60] Therefore, except in cases of extreme pain or ovarian endometriomas that hinder oocyte retrieval, endometriomas can be managed expectantly.