OOCYTE CRYOPRESERVATION

Oocyte Cryopreservation, is a method used to preserve reproductive potential in women.

The procedure involves collecting ovary cells from your ovaries, freezing them, and storing them for later use. A frozen ovary can be thawed, fertilized with sperm in a laboratory, and then implanted into your uterus (in vitro fertilization method).

Your doctor can help you understand the progression of the Oocyte Cryopreservation process, potential risks, and whether this fertility preservation method is right for you.

Why Is It Done?

If you have entered early menopause but still want to get pregnant or try to have children in the future, freezing ovaries may be an option.

The Oocyte Cryopreservation process, unlike freezing a fertilized ovary (embryo cryopreservation), does not require sperm. Only the ovary is frozen in this process. However, like with embryo freezing, you will need to use fertility drugs to stimulate the ovaries before collecting the ovaries.

You can think of Oocyte Cryopreservation as follows:

If you are undergoing cancer or other medical treatments that may affect your fertility and lead to early menopause, such as radiation or chemotherapy, some medical treatments can harm your fertility. Freezing ovaries before treatment allows you to preserve your chance of having biological children later.

Risks of Oocyte Cryopreservation

Oocyte Cryopreservation carries various risks, including:

Some risks associated with the medications used in treatment: The use of medications such as follicle-stimulating hormone or luteinizing hormone to induce ovulation can lead to ovarian hyperstimulation syndrome, a condition where the ovaries swell due to excessive stimulation of the ovaries. Symptoms include mild abdominal pain, bloating, nausea, vomiting, and diarrhea. In more severe cases, ovarian hyperstimulation syndrome can lead to fluid accumulation in the abdominal area and shortness of breath.

Risks associated with the ovary retrieval process: Rarely, the needle used to collect ovaries can cause bleeding, infection, or damage to the intestines, bladder, or blood vessels.

Risks associated with general anesthesia: Risks associated with anesthesia may arise as you undergo ovary retrieval.

If you use frozen ovaries to have a biological child, the risk of miscarriage will depend on your age when your ovaries were frozen.

Studies conducted so far have shown no additional increase in the risk of postnatal disability in babies born as a result of Oocyte Cryopreservation. However, more research is needed to confirm the safety of Oocyte Cryopreservation.

How to Prepare?

If you are considering f Oocyte Cryopreservation, consult with a doctor who specializes in this field.

Before starting the Oocyte Cryopreservation process, several screening tests should be performed, including:

Ovarian reserve tests: To determine the quantity and quality of your ovaries, your doctor may test the concentration of follicle-stimulating hormone (FSH) and estradiol in your blood on the third day of your menstrual cycle. The results can help predict how your ovaries will respond to fertility drugs. Additional blood tests and ultrasound imaging of the ovaries are used to assess ovarian status.

Infectious disease screening: You will be screened for specific infectious diseases such as HIV (AIDS) and hepatitis. Potentially infectious ovaries are stored differently from other ovaries.

Before Oocyte Cryopreservation, consider important questions, including:

How many ovaries do you want to freeze? Most experts recommend freezing a total of 20 to 30 ovaries per pregnancy, depending on your age and ovary quality, and thawing six to eight ovaries.

What to Expect During This Process?

During the Oocyte Cryopreservation Process:

Oocyte Cryopreservation involves multiple stages – ovary maturation (ovulation induction), ovary retrieval (oocyte pick-up), and freezing.

Ovary Maturation (Ovulation Induction)

At the beginning of your menstrual cycle, you will start treatment with synthetic hormones to produce more than one ovary per month, rather than the usual single ovary.

You may need several different medications for this:

• Medications for ovarian stimulation: Medications such as follicle-stimulating hormone or human menopausal gonadotropins are used to stimulate the ovaries.
• Medications to prevent early ovulation: Medications such as a gonadotropin-releasing hormone agonist or a gonadotropin-releasing hormone antagonist are used to prevent early ovulation.
• During treatment, your doctor will perform vaginal ultrasound scans to monitor the development of fluid-filled ovarian cysts (follicles) that contain the ovaries. Blood tests are used to measure your response to ovarian stimulant drugs. Estrogen levels typically increase as follicles develop.

When the follicles are ready for ovary retrieval – usually 8 to 14 days later – injections of human chorionic gonadotropin or other medications can help mature the ovaries.

Ovary Retrieval

Ovary retrieval is performed under vaginal ultrasound guidance. Technically, during this procedure, an ultrasound probe is inserted into the vagina to identify follicles. A needle is then guided through the vagina into a follicle. An aspiration device attached to the needle is used to remove the ovary from the follicle.

After ovary retrieval, you may experience cramping. Feelings of fullness or pressure may persist for weeks as your ovaries expand.

Freezing

Shortly after your unfertilized ovaries are collected, they are cooled to stop all biological activity and preserve them for future use. Your healthcare team may use substances called cryoprotectants to prevent the formation of ice crystals during the freezing process.

Cryoprotectants are used with one of two freezing methods:

Slow freezing method: This method initially uses low concentrations of cryoprotectants. As the temperature decreases and ovary metabolic rates decrease, higher cryoprotectant concentrations are used. The slow freezing method can also be used to protect ovaries from toxins in cryoprotectants.

Vitrification: In this method, higher concentrations of cryoprotectants are initially used, along with rapid cooling so that intracellular ice crystals do not have time to form.

After the Procedure

You should avoid unprotected intercourse to prevent unwanted pregnancy during the treatment process.

After the procedure, consult your doctor if you experience any of the following symptoms:

• High fever (38.6 C)
• Severe abdominal pain
• Weight gain of more than 2 kilograms within 24 hours
• Heavy vaginal bleeding – filling more than two pads per hour
• Difficulty urinating
• Results

Intracytoplasmic sperm injection (ICSI)

When you decide to use your frozen ovaries, they will be thawed first and then fertilized with sperm in a laboratory before being implanted into your uterus. Your healthcare team may recommend using a fertilization technique called intracytoplasmic sperm injection (ICSI). In ICSI, a single healthy sperm is injected directly into each mature ovary. Approximately 90% of ovaries survive freezing and thawing, and about 75% will successfully fertilize. Your chances of becoming pregnant after the ovaries are thawed depend on your age at the time of Oocyte Cryopreservation, ranging from about 30 to 60%. The chances of having a live birth in the future are lower for those who are older at the time of Oocyte Cryopreservation.

Remember that pregnancy rates may be lower when using frozen ovaries compared to fresh or frozen embryos. So, your chances are higher if you freeze your ovaries fertilized with sperm.