Egg Freezing
The eggs are retrieved for screening, and mature eggs are preserved through vitrification.
Overview
1. Stimulate and Retrieve
The treatment cycle is typically carried out over 2-weeks, beginning with your ovaries stimulated by hormonal injections to
boost your egg production and help the eggs mature.
The process is monitored by blood tests and transvaginal ultrasound assessments of the ovaries.
Once the ovaries have grown sufficiently, the eggs are retrieved via an out-patient procedure.
2. Assess and Freeze
Mature eggs are selected and put in a special solution containing substances (cryoprotectants), which help to draw water out and provide protection in the cells.
The eggs are then frozen either by cooling them slowly or by vitrification (fast freezing) and stored in tanks of liquid nitrogen.
3. Fertilise and Screen
When ready to use the eggs, eggs that have been frozen are thawed to be fertilised with sperm.
After fertilisation, the embryos develop and divide in culture until they are ready for genetic testing and/or transfer.
Embryos are screened and biopsy could be conducted for genetic testing to determine the presence of chromosomal abnormality and genetic disorders.
4. Transfer
Embryo transfer is a short procedure where embryos are inserted into the uterine cavity via a catheter, similar to a pap smear.
Before embryo transfer, the body needs to be prepared for the implantation procedures and may take another six weeks for the transfer to happen.
Reference Process and Timeline
- Meet your doctor
- Get medical advice
The first appointment with your doctor helps you gain a thorough understanding of the fertility preservation process, treatment procedures as well as the risks involved.
You should take this opportunity to evaluate if the doctor and clinic is right for you and the costs associated with your treatment.
You should form a view on the approximate treatment timeline, i.e. when you are starting your medication and when your egg retrieval date should be. The timeline would be refined as the treatment begins as it depends on the progress of your ovaries’ reaction to the medication.
Find out the preparation needed before treatment. Depending on your situation, they may ask you to get on or off birth control pills to regulate your cycle and provide specific dates on when to take your first and last oral contraceptives. Smoking could have an adverse impact on the egg retrieval count and quality and the doctor may advise you to refrain from smoking before and during your fertility treatment cycle.
Sometimes, some small operations may be needed, e.g. hysteroscopy, laparoscopic chromotubation, as part of the investigation before IVF.
- Complete health assessments
- Prepare for treatment
Typically, doctors would order testing of infectious diseases and fertility level via blood and urine samples before you begin the fertility treatment. They could include the following assessments.
Infectious diseases: Hepatitis B, Hepatitis C, HIV, Syphilis, Chlamydia, Rubeola, Rubella
Fertility and reproductive health: AMH level, Prolactin, Vitamin D, FSH, Estrogen, Progesterone, Pap Smear, Ultrasound for antral follicle count
Genetic diseases: Genetic testing, conducted by analyzing saliva samples, could also be required, especially if you are freezing embryos and/or have a family history of genetic issues.
- Conduct baseline test
- Learn to inject medication
Time: Usually within Day 1 – 3 of your menstrual cycle
The doctor or clinic would ask you to make an appointment during that time to conduct the baseline trans-vaginal ultrasound and blood assessment.
The nurse should work out a tentative calendar of your visits to the clinic for ultrasound and bloodwork and when to start the hormonal medication. The nurse would explain to you the hormonal medication you need to take and provide you the instructions for injection.
You should expect follow up visits to the clinic for ultrasound and blood work every 1-3 days during your treatment cycle to monitor your progress and determine when your ovaries are mature enough for egg retrieval.
- Inject medication
- Continue ultrasound, blood tests
- Manage side effects
Time: 1 - 2 weeks
To retrieve eggs for freezing or IVF, the key to success lies in maturing multiple eggs at once. Injections of the natural hormones FSH and/or LH (gonadotropins) are used to stimulate the growth of the ovarian follicles where the eggs reside.
To prevent premature ovulation, other medications would be used to avoid release of the eggs before they are ready. Blood tests and trans-vaginal ultrasound are conducted to monitor the growth of follicles and ovarian response.
Typically, you will administer hormonal medication in the form of injections daily by yourself. The nurse would instruct you on how to manage each medication and the time and/or frequency you should take them. It is normal to have skin irritation, such as swelling, redness, bruising in the injection site. Ovarian hyperstimulation could be a risk so you should monitor any side effects you experience and reach out to the doctor or clinic if necessary.
- Retrieve eggs from ovaries
- Prepare for recovery
Time: 20 – 40 minutes
Before egg retrieval, you will administer the “trigger shot” as instructed by your nurse to prepare your ovaries for the out-patient operation. Pay attention to the time of the day in which you need to inject the “trigger shot” as it is critical for the egg retrieval success.
General or partial anesthesia is provided to reduce discomfort before the retrieval procedures begin. Under ultrasound guidance, a thin, long needle will penetrate through the vaginal wall into the individual follicles to remove the matured eggs. Risks associated include bleeding, infection and trauma if other intra-abdominal organs are damaged.
Medications may be prescribed to you to help manage side effects and support our recovery after the egg retrieval procedures.
- Evaluate egg maturity
- Freeze and store eggs
After egg retrieval, the embryologist would examine the maturity of the eggs and only eggs that are mature would be frozen. Immature eggs may be cultured for another day and if they become mature, they would be frozen, otherwise immature eggs are discarded.
There are two ways for freezing: slow-freeze and vitrification (flash freezing). Compared to the older slow freezing technique, vitrification reduces the risks of ice crystal formation in the cell and is a more efficient procedure commonly used in the embryology laboratory.
Using sterilized liquid nitrogen, a cryoprotectant and cryo-specimen carriers, the eggs are frozen and stored within cryopreservation tanks. Liquid nitrogen is directly exposed to the eggs to maximize ultra-rapid cooling and minimize ice crystal formation. Hence, there is a theoretical risk of exposure to infectious organisms if the liquid nitrogen is contaminated.
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