By: Dr. Julie Rhee
Many women feel that as they reach their 20’s and 30’s that they juggle multiple goals which may include pursuing advanced education degrees and career goals, while trying to fathom the idea of starting a family. A woman’s ability to have children is very age dependent, as women are born with a finite number of eggs that they will have for the rest of their life and this egg pool gradually decreases as a woman ages and the reproductive window starts to close. To help women more easily plan their future, egg freezing (also known as oocyte cryopreservation) has become a viable option to help women better plan their future without missing out on the opportunity to build a family.
Oncofertility is egg freezing that can also be used for patients who are undergoing gonadotoxic therapy for cancer or other medical diseases. With appropriate counseling and collaboration with a patient’s entire medical team, egg freezing may offer the patient the ability to have children once done with medical treatment.
Historically, egg freezing was technically difficult due to the formation of ice crystals using slow freezing, which then would cause damage to the eggs when thawed. However, due to a newer technique of fast freezing called ‘vitrification’ egg freezing and thawing has become much more successful. Vitrification is a process in which tissue is flash frozen in an immediate glass-like state. As of 2000, researchers started to claim that vitrification provided benefits of cryopreservation without damage due to ice crystal formation and now, most IVF labs will use this technique to cryopreserve eggs, sperm, and embryos. Due to the dramatic improvement of success following oocyte cryopreservation as well as promising safety data, the American Society of Reproductive Medicine lifted the ban in 2012 that egg freezing was experimental.
Success rates after oocyte cryopreservation depend on a patient’s diagnosis, history, as well as age at which eggs were frozen. Due to increased chromosomal abnormality in eggs as they age, oocyte cryopreservation is recommended at younger ages. In a 2013 meta-analysis of more than 2,200 cycles using frozen eggs, the probability of having a live birth decreased dramatically every five years starting at age 25. Eggs have approximately 90% chance of thawing. At younger ages, frozen eggs work as well as fresh eggs.
How can we judge egg reserve?
We check ovarian reserve with a blood test looking at anti-mullerian hormone (AMH) and do an antral follicle count along with FSH between cycle days 2-5 of a menstrual cycle looking at the small resting follicles of the ovary that could potentially become eggs. This gives us a good idea of how many oocytes may be able to be retrieved. Vios Pulse Fertility Wellness Check Up is a great and easy way to check this for only $99.00. Vios is unique in including AMH testing in this low cost testing package.
So, how does egg freezing work?
The rest of the process is similar to IVF: the patient undergoes 8-10 days of ovarian stimulation using injectable medications and during this time, she would come in for ultrasounds and bloodwork to measure ovarian response. Once the follicles appear ready to be retrieved, she would take a “trigger shot” which matures the oocytes and gets them ready for the egg retrieval. She will undergo the egg retrieval process which usually takes about 15 minutes and is done under conscious sedation. The eggs are retrieved transvaginally and then immediately vitrified in our Vios IVF lab.
How long do eggs last?
The exact time they last is unclear since it is a new technology. Because vitrification places the eggs in a ‘glass like state’, the eggs seemingly may be frozen indefinitely.
How many eggs should be frozen?
It seems that at least 15 eggs is a great number to optimize the chance of getting a baby. Sometimes it takes more than one egg retrieval to get to that number.
What is the difference between freezing eggs vs. fertilized eggs?
If there is a partner or if willing to use donor sperm, embryos can also be created and have a 95-98% chance of surviving as compared to 90% with eggs.
In summary, egg freezing is a viable option for women who are not yet ready to build a family but would like the opportunity to do so later. Egg freezing is also a promising option for women undergoing medical or chemotherapy that may be destructive or toxic to the ovaries. Although there is no age cut off for egg freezing, it is highly recommended in one’s 20’s or 30’s in order to maximize chances of having healthy eggs frozen which are more likely to work when ready to use.