Alpesh Doshi, Consultant Embryologist & Founder of IVF London, is talking about the role of the embryologist in egg freezing and the outcome of the whole IVF treatment.
Egg freezing – definition
Alpesh Doshi started his presentation by explaining what egg freezing means and how it is done. Egg freezing is retrieving the eggs from the ovaries and then cryopreserving them. Cryopreservation means storing the biological cells at a very low temperature, as low as minus 196 degrees in liquid nitrogen, and at this temperature, all the activity in the cells, and all biological function stops. Hence, you can preserve them without deteriorating the quality of the eggs themselves. It is one way for fertile women to preserve their fertility so they can have a family in the future.
Women choose to freeze their eggs if there is a medical condition which can potentially make them infertile, such as cancer. The cancer cure, chemotherapy, or radiotherapy, are the treatments offered to women who may want to consider some cancer treatment, and as a result, women may lose their fertility because the drugs that they’re given are very harsh, and that can also make them infertile. Before women consider any kind of chemotherapy or radiotherapy, they may have an option to freeze their eggs to preserve their fertility for the future.
At the same time, there’s a huge number of women are now considering fertility preservation purely because they’re not ready to have a child for various reasons. Either it’s the career, it may be because they want to get a fair education, or they didn’t find the right partner. Another reason can be if a woman is a member of the Armed Forces and is deployed to a war zone, also a lot of men freeze their sperm before they are deployed to Afghanistan or Iraq in the event they do not have the potential of having their child or naturally producing sperm. Another reason can be a transitioning female to a male may want to consider freezing their eggs.
Today, a social trend toward delaying childbearing has been observed in women of reproductive age. This delay is due to different factors such as:
- academic education
- other self-fulfilling activities
There are common dilemmas women face these days in terms of trying to balance the pressures of modern-day limits versus a reproduction. Seeking a long-term relationship, getting pregnant, considering maternity or taking care of the child during the first years of life. If they take maternity leave, that could potentially affect their careers, and they are opposed to trying to balance the amount of time they want to spend at home once the baby is born in the early years.
Fertility & woman’s age
What role does age play? A woman’s chances of conceiving naturally fall as she gets older because the quality and the number of eggs drop with age. Egg freezing is a process which allows patients to preserve their fertility by freezing their eggs when a woman is young, and the eggs are of the highest quality. The graph presented demonstrates what is the decline in fertility as women age, after 35 years old, there is a very rapid decline in a woman’s fertility potential, and the quality and the number of eggs in their ovaries do drop. In the 40s, the drop is o high that the chances of conception are very slim, and at the same time, the risks of genetic abnormalities in the babies can be very high as well. The quality of and the number of eggs goes down with age, but at the same time, the risk of miscarriage goes higher. With age, live birth rate drops while the rate of miscarriage goes up. There are more chromosomal errors in the embryos as there is an increased risk of genetic abnormalities, and the risk of having an ongoing pregnancy with a genetically abnormal embryo also increases with age, such pregnancies potentially can be terminated or result in a live birth of children with some major disabilities. The age-related increase in genetic abnormalities is not linear. Rather, the rate sharply increases when women reach their mid-30s. Typically, after 37 or 38 years of age, there is a very rapid decline in the quantity and quality of the eggs.
The American data has been published that 1 in 5 American women has chosen to have her child much later. One of the studies showed that from 2000 to 2012, there was a 24% increase in women having their first child between the age of 35 and 39. Around 35% of women decided to have their first child in their 40s. This translates into a 50-fold increase in the annual number of IVF procedures performed in the US since 1985, half of which are currently performed on women over age 35.
Age has an adverse effect on IVF outcomes. The chances of live birth after a cycle of IVF plummets from 41% at the age of 35 to 4% after the age of 40. The extent of this fertility decline is not appreciated by most non-infertility physicians, the public, or men and women who are delaying childbearing. Hence, it’s very important to make yourself aware of fertility education. The live birth rate at 35 years old is around 41.5%, and at the age of 44, it is less than 1%.
Egg freezing process
There are 3 main steps of the whole egg freezing process. The first step is the workup, which includes an initial consultation to discuss medical history and suitability for egg freezing. Some basic tests to check the woman’s hormones, such as AMH (Anti-Müllerian hormone), a good predictor of women’s fertility, and AFC (Antral follicle count) to check how many tiny follicles are present in each ovary. This could give your consultant an indication in terms of how the fertility hormones will reflect when stimulation is given. The combination of the antral follicle count and the AMH gives a very tailored stimulation regime and helps determine the right dose to give for hormonal stimulation to mature or grow those follicles in the ovary. You will be asked to do virology screening, full blood count, HIV, chlamydia, rubella, and gonorrhoea tests. The second step is the preparation, whereby you will have a nurse consultation, you will do all your consent forms, all the paperwork, all your injections are going to be taught, and your medication can be purchased as well. Step 3 is the actual treatment itself, where you would start injecting yourself with fertility hormones and then over 10 to 12 days, you’d be monitored in terms of the scans to see how those follicles are growing, and then there is an egg collection. Finally, freezing of those eggs. From the time a woman has her period, and if we’re using a short protocol, the whole process can be finished in 2 to 3 weeks from start to finish. A woman only needs around 5 to 6 visits to the clinic to complete the whole egg freezing cycle.
Once the eggs are collected they are stripped of all the cells around the egg because when egg freezing is performed we do not need any of those external cells as its role is to nurture the egg within the ovary, but once the eggs are already out of the array all the peripheral cells can be removed to maximize the survival rate of the eggs. To freeze the eggs, they need to be dehydrated, meaning the water content has to be removed because having water in the eggs can make them very susceptible to being damaged during the freezing and thawing procedures. Therefore, removing the water is crucial, and if this procedure is not done properly or it’s not done with skill, the eggs will not survive the freezing procedure. Finally, once the eggs are dehydrated through various solutions, they’re frozen in liquid nitrogen, the straws containing the eggs can then be stored in tanks containing liquid nitrogen for many years.
Fresh vs. vitrified oocytes – comparison
Is there a difference in outcomes between fresh eggs and frozen eggs, and that would be a very good question to ask and then mean some studies that have shown that there is no difference in various parameters or various embryology beliefs parameters between fresh and frozen eggs? One of the studies has shown that there is no difference in fertilization rate, embryo development rate, and most importantly, there is no difference in blastocyst formation rates. Frozen eggs can have the same potential as fresh eggs.
Egg freezing & law
In the UK, there is a law governing egg freezing, so the regulatory body called the Human Fertilisation and Embryology Authority (HFEA) ensures that all patients receive the best level of care by monitoring and inspecting clinics. They have set a 10-year storage limit for frozen eggs which is currently under review. This limit can only be increased to 55 years if a woman is diagnosed with premature infertility.
If you’re a single woman or you’re in a same-sex relationship you may want to use donor sperm, and there are very well-established UK and European banks to give you a wide selection of donors to choose from. The selection begins by reviewing donor profiles, and the staff assists you through that process.
When you’re ready to use your frozen eggs they would have to be thawed out. Once they’re thawed out, the method to inseminate them with the sperm is using a procedure called Intracytoplasmic Sperm Injection (ICSI), this method helps to initiate fertilization in the frozen eggs. The embryos that are created by inseminating those frozen eggs can then be monitored for 3 to 6 days in the laboratory, and then 1 or 2 embryos can be transferred into the uterus to establish a pregnancy.
The main factor influencing the chance of success is the age at which your eggs are frozen. The earlier you freeze them, the higher the success rates. In terms of pregnancy rates, vitrification is a very successful freezing technology, which is between 90 to 95% survival rate.
There is a study that has shown that typically the survival rate of the eggs can also go down with age, but even after 40, we expect survival rates above around 85%, it’s important to understand that the pregnancy rate or clinical pregnancy rate per egg thawed is 6%. If there is a 35-year-old woman who’s frozen 10 eggs and has 10 surviving eggs, her chance of getting pregnant is around 60% of all those 10 eggs have been thought out.
Egg freezing – risks
- ovarian hyperstimulation syndrome (OHSS), which means that ovaries over-react to fertility drugs, it’s very rare, and it’s more precipitating in patients who have PCOS (less than 3%)
- surgical complications of egg collection (less than 1 in 2000)
- eggs surviving the freezing and thawing process (over 95%)
- there is no evidence that the stimulation hormones increase the risk of ovarian cancer
- there is no evidence to suggest that stimulation causes early menopause