The impact of the coronavirus epidemic and lockdown is not limited to the economy; it also separates couples and families, especially the expats who relocate to other countries for work. Some couples may need to delay their family planning due to distance, impacting on fertility. Oocyte freezing may become one of the solutions that they can consider in order to preserve their eggs for future use. Dr Yeung Wing Yee Tracy, Specialist in Obstetrics & Gynaecology, explains more about oocyte freezing and clarifies some myths.
Who might consider oocyte freezing?
At first, oocyte freezing technology was developed for women with diseases that might affect their fertility, such as cancer patients who need chemotherapy or women who suffer from severe gynaecological diseases, like ovarian tumours, endometriosis and so on. For healthy women, fertility declines from early 30s. However, some women may not have plans to get married and have a family soon due to their own life planning; they may also consider oocyte freezing for future use.
What are the factors affecting the fertility of women?
Age is a major factor affecting the fertility of women. Between 25 and 35 years, the successful rate of pregnancy is higher. From the age of 35, fertility will significantly decline; the negative slope becomes even steeper after 38. Hence, it’s advised that the optimal time for oocyte freezing is before 35, when the oocytes are still in better quality.
How can women know their fertility?
Women can check their ovarian reserves through an anti-Mullerian hormone (AMH) test and ultrasound. An AMH test is an important blood test to determine the ovarian reserves of a woman. AMH value declines as women age; that means the higher the ovarian reserve, the higher her AMH value. The high value also reflects better response to hormonal injections, which is a major part of the oocyte freezing procedure.
When a woman turns 35, the AMH value will drop as the quantity of oocytes is reduced. Women that have fewer remaining follicles and those that are close to menopause have lower AMH levels. If a woman finds her AMH level is lower than the normal range, it may be a sign that she needs to plan ahead if she wants to be a mother in the future.
Women can also get an ultrasound to determine the number of ovarian antral follicles, which correlates with the response of ovaries to the hormonal injections when they do oocyte freezing. However, both tests cannot determine the quality of oocytes.
What is the procedure of oocyte freezing?
Oocyte freezing consists of a few steps.
Doctor will discuss the procedure, risks and future use of eggs. Based on the reports of the AMH test and ultrasound, the doctor decides the medication and the dose of hormonal injections needed to stimulate the ovaries for follicular growth.
#2 Hormonal injections
Women will receive an ultrasound on the second or third day of their period to check if there is any cyst in the ovaries. If the condition of the ovaries is normal, the woman needs to receive hormonal injections for 8 to 10 consecutive days to stimulate the ovaries. The number of oocytes varies with the age and ovarian reserve of individual women. Within this period, 2 to 3 ultrasounds are required to check the response of ovaries, and dose adjustment may be needed.
#3 Maturity of oocytes
When the follicles develop to a good enough size, the woman will receive an ovulation trigger shot to make the eggs mature. In around 36 hours, when the oocytes become mature, it is time to retrieve the eggs.
#4 Retrieval of eggs
With the help of ultrasound, the doctor will retrieve the eggs through the vagina and the mature oocytes will be frozen. The procedure takes place in IVF centres, and usually takes 30 to 45 minutes. The woman can choose to do it under local anaesthesia or sedation. After the procedure, the woman may leave after taking a rest for 1 to 2 hours. No hospitalisation is needed.
#5 Future use
The preserved oocytes can be taken out for fertilisation and to complete the IVF cycle when she is ready for a child. In Hong Kong, current regulation requires the woman to be legally married.
How many eggs should a woman freeze?
It depends on the age, her expectation on pregnancy rate and the number of pregnancies desired. Younger women tend to have eggs with higher quality, so freezing 10 to 20 eggs would allow a reasonable chance of successful pregnancy, and she may need to do one cycle of procedure only. As the quality of eggs of women declines with age, they may need to have more than one cycle of the procedure in order to get enough oocytes for a good chance of pregnancy.
What is the local regulation on oocyte freezing?
The oocytes can be stored for a maximum of 10 years according to the local regulation in Hong Kong. And they can only be used after being legally married, with a history of difficulties in getting pregnant.
What is the possibility to get cryopreserved oocytes transferred to other countries?
The cryopreserved oocytes can be transferred to IVF centres overseas. As the regulation on oocyte freezing varies in different countries, women are advised to check the local regulation before making the decision.
How much does it cost for egg freezing in Hong Kong?
The costs vary with different factors, including the dose of hormonal injections and whether anaesthesia is applied. Usually, it costs around HK$70,000 to HK$90,000 for the whole treatment including consultations, monitoring, hormonal injections, laboratory fees and the oocyte retrieval procedure. After the retrieval of oocytes, there will be an annual maintenance fee charged by the laboratories at around HK$10,000.
What is the success rate of oocyte freezing?
In the most recent decade, due to the application of vitrification, the survival rate of cryopreserved oocytes exceeds 90%, which is a much higher rate than in the past.
How does the procedure affect women’s health?
Some women may experience mild abdominal pain and discomfort after receiving hormonal injections, but the vast majority can carry on their usual daily activities as usual. Major risks include ovarian hyperstimulation, ovarian torsion and surgical risks, which are all rare (less than 1%).
What is your view on the myths of oocyte freezing causing early menopause?
Some women are worried that oocyte retrieval will lead to early menopause. Actually, the eggs retrieved are the ones prepared by the body every month. Even if they are not extracted, the oocytes will disappear at the end of the cycle, and a new batch of oocytes will be produced in the next cycle. Oocyte freezing is not using future ovarian reserves, hence it will not cause early menopause.
Some may worry about the risk of cancer, especially of ovarian cancer with the use of hormonal injections. However, current scientific evidence does not suggest an increased risk.
The above information is provided by Dr Yeung Wing Yee Tracy, Specialist in Obstetrics & Gynaecology
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