Endometriosis and Fertility Preservation — When to Freeze Eggs

Endometriosis can quietly erode ovarian reserve over years. For young women with severe disease or those planning future pregnancy, fertility preservation can be a high-impact decision. This page explains who should consider it, when, and how.

1. Why endometriosis threatens ovarian reserve

Severe endometriosis with endometriomas, especially bilateral, is associated with reduced AMH and antral follicle count. Surgery on the ovary further reduces reserve, particularly with repeat operations or coagulation-heavy technique. The combination of disease progression and iatrogenic damage can deplete reserve before fertility is needed.

2. Who should consider fertility preservation

Young women (under 35) with severe endometriosis; bilateral endometriomas, especially over 3 cm; AMH below 1.0 ng/ml; planned ovarian surgery; recurrent endometriomas after prior surgery; family history of premature ovarian insufficiency; planning to delay pregnancy by several years.

3. What fertility preservation involves

Standard IVF stimulation with FSH for 10–12 days; egg retrieval under sedation; vitrification (rapid freezing) of mature oocytes; long-term storage in liquid nitrogen. Total time: about 3 weeks per cycle. Multiple cycles may be needed to bank adequate egg numbers. Embryos can be frozen instead if a partner is identified.

4. How many eggs are enough

10–15 mature frozen eggs at age 35 or younger gives reasonable chance of a future live birth, about 50–70% cumulative. At age 38–40, 20–25 eggs may be needed for similar odds. Multiple cycles often needed to reach these numbers. Each clinic should give written, age-stratified outcome data for their own freeze-thaw success.

5. Timing, before surgery is best

Egg freezing before ovarian surgery preserves whatever reserve currently exists. After ovarian cystectomy, AMH and antral follicle count typically drop, making subsequent egg retrieval less productive. If ovarian surgery is planned, the conversation about fertility preservation belongs before surgery, not after.

6. Combining surgery and preservation

For some patients, an egg freezing cycle before planned endometriosis surgery is optimal. Stimulation in the context of active endometriosis is generally well tolerated. Surgery then proceeds at the post-retrieval ovarian rest period. This combined strategy maximises both pain control and future fertility options.

7. The cost-benefit conversation

Fertility preservation is an investment in optionality. Many women never use frozen eggs because natural conception works. The decision rests on: severity of current reserve threat, age, partner status, future fertility goals, financial capacity, and personal risk tolerance. There is no universally right answer.

8. Limitations to understand

Frozen eggs do not guarantee future pregnancy. Survival after thaw is excellent (over 90% with vitrification). Fertilisation rates are normal. Live birth per egg thawed is approximately 6–10%. Eggs frozen at older ages have lower per-egg success. Honest counselling about realistic outcomes is essential.

Frequently Asked Questions