Ethanol sclerotherapy of endometriomas by the vaginal route

Quick answer

Ethanol sclerotherapy (alcohol ablation) of an endometrioma consists of puncturing the ovarian cyst under transvaginal ultrasound, emptying it, then injecting alcohol for about ten minutes to destroy its inner wall before aspirating it. It is offered to selected patients, notably with a large, painful cyst, recurrence after surgery, or an ovarian reserve to preserve. Recurrence remains possible (around 10 to 30% in most series) and the decision is made case by case with the gynaecology team.

Endometriosis and ovaries: being treated in Paris

In Paris, Cochin Hospital AP-HP (14th arrondissement) offers sclerotherapy of ovarian endometriomas by the vaginal route and cryoablation of abdominal wall endometriosis. Pelvic MRI for endometriosis is performed only at the request of the gynaecologists of Cochin Port-Royal (appointments via gynecochin.fr).

Request an opinion (abdominal wall endometriosis) · All treatments at Cochin

What is an endometrioma, and why treat it?

An endometrioma is an ovarian cyst filled with a brownish fluid, which is menstrual blood trapped in endometriotic tissue implanted on the ovary ("chocolate cyst"). It can grow cycle after cycle. When it becomes large it can cause pelvic pain, pain during periods or intercourse and a feeling of heaviness, and can make egg retrieval harder during in vitro fertilisation (IVF).

A small endometrioma without symptoms is not always treated. Management is discussed in a multidisciplinary meeting with the gynaecologists and, if needed, the reproductive medicine physicians. The reference treatment for a symptomatic cyst remains laparoscopic cystectomy, but it exposes to a drop in ovarian reserve, particularly with bilateral cysts or repeated surgery.

For an overview of the disease, see Endometriosis: definition and symptoms and our endometriosis care.

What does sclerotherapy involve?

It is a minimally invasive, ultrasound-guided procedure with no incision. The needle passes through the vaginal vault to reach the ovary, using an endovaginal ultrasound probe. The principle is to empty the cyst and then chemically destroy its inner wall with ethanol, to reduce the risk of it filling up again, while leaving healthy ovarian tissue in place.

It follows the same principle as the percutaneous alcoholization we perform for other cysts (kidney, liver, thyroid). It should not be confused with cryoablation of abdominal wall endometriosis, which treats an abdominal wall nodule with cold.

Who is it for?

The technique is discussed in the following situations, after work-up and a multidisciplinary opinion:

• a large, painful endometrioma, with pain attributed to the cyst;
• recurrence of an endometrioma after a first surgery, to avoid reoperation;
• bilateral cysts or an already low ovarian reserve (low AMH), where the aim is to spare ovarian tissue;
• a cyst hindering egg retrieval before IVF (aspiration, with or without sclerotherapy, is then reserved for this specific case according to the French CNGOF and HAS guidelines);
• a patient who declines surgery or for whom it carries a high risk (adhesions, anaesthetic risk).

When sclerotherapy is not indicated: suspicion of a malignant or atypical lesion on imaging (vegetation, Doppler vascularisation), a cyst not reachable by the vaginal route (interposed bowel loop), ongoing pelvic infection, uncorrected coagulation disorder. No procedure is offered for a tiny or asymptomatic cyst either.

How is the procedure performed?

1. Before: consultation, ultrasound and pelvic MRI to characterise the cyst and rule out a suspicious lesion, AMH measurement if a pregnancy is planned, coagulation tests, possible interruption of anticoagulants.
2. Set-up: sedation or general anaesthesia most often (sometimes local), antiseptic cleaning of the vagina, preventive antibiotic.
3. Puncture: under endovaginal ultrasound, a fine needle (15 to 16 G) is introduced into the cyst in a single pass, then its content is fully aspirated. The needle stays in place until the end to avoid any leakage.
4. Rinse: the cyst is flushed with saline until the fluid is clear.
5. Sclerotherapy: ethanol (95 to 96%), at about 60% of the aspirated volume, is injected and left in contact with the wall for about 10 minutes, then fully aspirated.
6. After: a few hours of monitoring. Same-day discharge is usual. An ultrasound check is arranged later, and hormonal treatment is discussed to limit recurrence.

Some teams leave a small catheter in place for two ethanol sessions 24 hours apart. This variant gave good results in a small series but is less widespread.

What are the results?

Published data come mostly from retrospective series, with few comparative trials. They point in the same direction:

• High technical success: 97% (112 of 115 procedures) in a 2026 Turkish series, about 90% in the French series by Miquel (11% failures: ethanol leakage, inaccessible cyst or impossible puncture).
• Recurrence: 8% at one year in the Italian series by Gatta (50 patients), 25% (22% at one year, 29% at two years) in the 2026 Turkish series, and 13% (ethanol left in place) versus 32% (ethanol removed quickly) in the series by Hsieh (108 patients). Rates vary with the definition of recurrence, cyst size and body mass index.
• Volume reduction: in the study by Zeng (22 patients, two-session catheter technique), mean diameter fell from 5.5 to 1.4 cm at six months.
• Pain: pain scores fall in several series but variably from patient to patient, and the data are less robust than those on cyst volume.

An older systematic review reminds that simple aspiration, without a sclerosing agent, very often recurs (29 to 92% after a single puncture), and that the contribution of ethanol varies between studies. Hence the importance of a standardised technique and rigorous patient selection.

Fertility and ovarian reserve

This is often the central question for young patients. What the data say:

• AMH, a marker of ovarian reserve, fell modestly in the 2026 Turkish series (median -0.12 ng/mL at six months) and without significant difference in the Zeng study. In a Taiwanese series, the fall was clearer (24%) when ethanol was left in the cyst than when it was aspirated (3%).
• A short series of laparoscopies performed after sclerotherapy showed no excessive adhesions and no alteration of the ovary's appearance.
• The French guidelines (CNGOF-HAS) state that ethanol sclerotherapy lowers the recurrence rate of endometriomas without impairing IVF results, whereas a second surgery would have a harmful effect. They do not, however, recommend systematic puncture before IVF to improve pregnancy chances.

These data are observational. The choice between sclerotherapy, surgery or watchful waiting when a pregnancy is planned is made with the reproductive medicine team.

What are the risks?

Sclerotherapy is generally well tolerated but is not risk-free. In the largest published French series (126 patients, 157 cysts treated, standardised protocol under general anaesthesia):

• complications occurred for 9.5% of treated cysts, the great majority minor (7% grade I);
• 2 of 126 patients (1.6%) had an ovarian abscess requiring specific management;
• 1 patient (0.8%) had ethanol toxicity (grade IV);
• no fatal complication was observed.

The 2026 Turkish series reports complications in 8.8% of patients, none of grade IIIb to V. Risks specific to the procedure are pelvic pain, intracystic or vaginal bleeding, infection, ethanol leakage into the pelvis (which stops the procedure) and, exceptionally, injury to a neighbouring organ. Antibiotic prophylaxis, single-pass puncture and ultrasound monitoring for the absence of leakage aim to reduce them.

Seek urgent care after the procedure for: fever, chills, increasing pelvic pain, unusual malaise or drowsiness, heavy vaginal bleeding. In a life-threatening emergency, call 15 (or 112).

Sclerotherapy, surgery, simple aspiration: how to choose?

Indicative comparison drawn from non-randomised series. It does not replace the opinion of the team that knows your file.

Our care at Cochin

Each file is discussed with the gynaecologists and, if needed, the reproductive medicine team of the centre. The interventional radiologist reviews the MRI, checks that the cyst can be reached by the vaginal route and discusses with you the expected benefits, risks and alternatives. No procedure is offered without having ruled out a suspicious lesion.

To request an opinion, you can use the contact form, selecting the reason "Endometriosis", and attaching if possible your latest pelvic MRI and any operative report.

Request a medical opinion → · Pre-consultation questionnaire → · Understanding endometriosis → · Abdominal wall cryoablation →

Scientific references

• Aslan B, Kaplan NB, Atabekoğlu C, Sönmezer M, Şükür YE et al. Risk factors for recurrence and safety outcomes after ethanol sclerotherapy for ovarian endometriomas. J Minim Invasive Gynecol 2026. doi:10.1016/j.jmig.2026.09.471
• Miquel L, Liotta L, Pivano A, Gnisci A et al. Ethanol endometrioma sclerotherapy: safety through 8 years of experience. Hum Reprod 2024. doi:10.1093/humrep/deae014
• Zeng CH, Cao Y, Shin JH, Kim JH et al. Safety and clinical outcomes of two-session catheter-directed sclerotherapy using ethanol for endometrioma. Cardiovasc Intervent Radiol 2024. doi:10.1007/s00270-024-03700-5
• Huang L, Chang MY, Shiau CS, Hsieh TT et al. Changes in anti-müllerian hormone after ultrasound guided aspiration and ethanol sclerotic therapy of ovarian cyst. Taiwan J Obstet Gynecol 2021. doi:10.1016/j.tjog.2021.03.021
• Dymanowska I, Frankowska K, Moqbil S, Abramiuk M et al. Laparoscopic assessment of the ovaries after resolving the endometriomas with ultrasound-guided transvaginal ethanol sclerotherapy. Gynecol Minim Invasive Ther 2026. doi:10.4103/gmit.GMIT-D-25-00055
• Chauffour C, Pouly JL, Gremeau AS et al. Endometrioma and management by assisted reproductive technology: CNGOF-HAS endometriosis guidelines. Gynecol Obstet Fertil Senol 2018. doi:10.1016/j.gofs.2018.02.014
• Gonçalves FC, Andres MP, Passman LJ, Gonçalves MO, Podgaec S. A systematic review of ultrasonography-guided transvaginal aspiration of recurrent ovarian endometrioma. Int J Gynaecol Obstet 2016. doi:10.1016/j.ijgo.2015.10.021
• Gatta G, Parlato V, Di Grezia G, Porto A, Cappabianca S, Grassi R. Ultrasound-guided aspiration and ethanol sclerotherapy for treating endometrial cysts. Radiol Med 2010. doi:10.1007/s11547-010-0586-0
• Hsieh CL, Shiau CS, Lo LM, Hsieh TT, Chang MY. Effectiveness of ultrasound-guided aspiration and sclerotherapy with 95% ethanol for treatment of recurrent ovarian endometriomas. Fertil Steril 2009. doi:10.1016/j.fertnstert.2008.03.056

Why this page is trustworthy

Written by the Interventional Radiology team of Cochin Hospital AP-HP, Université Paris Cité, and reviewed by an interventional radiologist of the department. Last updated: October 2026.

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