Ovarian Tissue Freezing
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in Fertility Care
Ovarian tissue freezing is an advanced fertility preservation technique where a piece of ovarian tissue (usually the outer layer called the cortex, which contains immature eggs) is surgically removed, frozen, and stored for future use.
Ovarian Tissue Freezing
What it is ?
Ovarian tissue freezing is an advanced fertility preservation technique where a piece of ovarian tissue (usually the outer layer called the cortex, which contains immature eggs) is surgically removed, frozen, and stored for future use.
Unlike egg or embryo freezing, which requires mature eggs, ovarian tissue freezing preserves a large number of immature eggs within the tissue itself. Later, the tissue can be reimplanted back into the woman’s body, where it may restore hormone function and fertility.
It is especially valuable for young girls and women who cannot delay urgent medical treatments like chemotherapy or who cannot undergo egg retrieval.
Causes
Ovarian tissue freezing is mainly considered when traditional methods like egg or embryo freezing are not possible.
Medical Causes
- Cancer treatments (chemotherapy, radiotherapy, bone marrow transplants) that may destroy ovarian function.
- Women with genetic conditions (e.g., Turner syndrome, BRCA mutations) that increase the risk of early ovarian failure.
- Autoimmune disorders where treatments damage the ovaries.
- For patients undergoing ovarian or pelvic surgery that might impair fertility.
Personal/Social Causes
- Women wishing to delay childbearing for personal or career reasons, especially when egg freezing is not an option.
- Prepubertal girls (since they cannot produce mature eggs for freezing).
When it is considered ?
- Before cancer treatment that risks ovarian failure.
- In young girls who cannot undergo egg freezing.
- For women who cannot delay urgent medical treatment to undergo hormone stimulation for egg retrieval.
- In cases of premature ovarian insufficiency (POI) or risk of early menopause.
- When hormone stimulation is not possible or contraindicated (e.g., hormone-sensitive cancers like breast cancer).
Types
Cortical Strip Freezing (Most Common)
- Small pieces of ovarian cortex containing immature eggs are frozen.
- Later transplanted back into the ovary or near the fallopian tubes.
Whole Ovary Freezing (Experimental)
- Freezing the entire ovary with its blood vessels.
- Aimed at restoring full ovarian function but still under research.
In Vitro Follicle Maturation (Emerging)
- Immature eggs within ovarian tissue are matured in the lab before being fertilized.
- Not yet standard but holds promise for the future.
Step Process
Procedure
Step 1 : Surgical Removal
- Done through laparoscopy (keyhole surgery) or laparotomy.
- A portion (or whole ovary) is removed.
Step 2 : Tissue Preparation
- The ovarian cortex is cut into thin strips containing thousands of immature eggs.
Step 3 : Freezing (Cryopreservation)
- The tissue is treated with cryoprotectants to prevent ice damage.
- Preserved using slow freezing or vitrification techniques.
Step 4 : Storage
- Stored in liquid nitrogen at –196°C for years.
Step 5 : Thawing & Transplantation
- When the woman is ready, the frozen tissue is thawed.
- Transplanted back into the pelvis (orthotopic transplantation) or sometimes under the skin of the forearm (heterotopic transplantation).
- The tissue may resume natural hormone production and release eggs.
Step 6 : Fertility Treatment
- If ovulation resumes, pregnancy can occur naturally or via assisted reproductive techniques like IVF.
Benefits
- Only option for prepubertal girls or women unable to undergo egg retrieval.
- Restores both fertility and hormonal function (helping with estrogen production, menstrual cycles, and preventing premature menopause).
- Allows for natural conception in many cases after tissue reimplantation.
- Provides long-term fertility preservation, with storage possible for many years.
Results & Success Rates
- Restoration of Ovarian Function : Over 90% of women regain hormone function after reimplantation.
- Pregnancy Rates : More than 200 live births worldwide have been reported (and rising each year).
Success Depends On:
- Age at the time of tissue freezing (younger women have higher chances).
- Health of the ovarian tissue after thawing.
- Type of cancer or treatment received (some therapies may damage ovarian tissue before freezing).
- Longevity : Restored ovarian function typically lasts 5–10 years after transplantation.