The Beginners Guide to Egg Freezing

August 21, 2019 | admin

Yes Mom

More and more of us seem to be delaying our plans for marriage or starting our family as we focus on building our careers, finding work-life harmony or the right partner to have a child with. By the time we feel ready to get pregnant and have a child, some of us may have already crossed our mid-thirties or forties. But, we can make smart choices such as freezing our healthy eggs while we are still in our mid-twenties or early thirties. Being proactive about such choices can help us win against our ticking biological clocks and choose to have a baby at a much later stage in our lives.

Alannah Roberts from Stourbridge, UK, froze some of her eggs as a teenager at the age of 17. Two years before that, she had been diagnosed with cancer of the blood which can lead to infertility. Having survived cancer three times, she decided to use her frozen eggs at the age of 30. She was elated to find herself pregnant after using her 13-year-old frozen eggs. Her daughter Faith Roberts was born 14 years after she chose to freeze her healthy eggs. 

Former Miss World Diana Hayden, from India, had her eggs frozen when she was 33-years-old and eight years later, they were thawed and used successfully. At the age of 42, she gave birth to her first child, instilling hope in countless Indian women who wish to focus on their careers first and are in no rush to become moms.

We never know what surprises life has in store for us. It’s always best to be prepared and stay one step ahead. Egg freezing has empowered women to take control of their biological clock and fertility choices.

Egg Quality and Healthy Pregnancy

A newborn female baby already has, in her, all the eggs she will ever have in her life. As she grows up and matures, her eggs age with along her. Her best reproductive years are in her 20s and early 30s. From her mid to late 30s, the quality and quantity of a woman’s eggs decrease and over the age of 40, this scenario worsens. 

Her chances of conceiving a baby also reduce as she crosses what nature considers to be her optimum child-bearing years. There are many pregnancy risks associated with the increasing age of women, such as higher chances of chromosomal abnormalities, birth defects, miscarriage, and difficulty in conceiving. Now, what if there was a way to stop this biological clock, halt the aging process and preserve the younger, healthier eggs until a woman feels ready to have her child?

This is where the technique of ‘Egg Freezing’ comes to her rescue. Egg freezing can help extend a woman’s childbearing years by helping save her ability to get pregnant in the future. This miracle of modern science is becoming an increasingly attractive option for women who prefer to have a child in her forties, fifties or even later than that.

Cryopreservation

It has been a popular theme in many sci-fi movies, where the main character wakes up in a cryo-tank or spaceship travelers are put to cryosleep so they don’t age during their years-long interstellar journeys. Cryogenic tanks, called cryotanks in short, are special containers used to store frozen biological material.

So what exactly is cryopreservation and is it just science fiction?  Cryopreservation is actually a technique that has been in practice for decades in various branches of the medical world. This process involves freezing biological material at extreme temperatures, at which all biological activities in the cells stop completely. This includes even the biochemical reactions that lead to DNA degradation and cell death. Temperatures used are as low as -196 °C/-321 °F and the most commonly used medium is liquid nitrogen.

Oocyte Cryopreservation or Egg Freezing

Egg freezing, which allows women to freeze their own eggs for producing healthy offspring in the future, also follows this same technique. Scientifically termed, “oocyte cryopreservation”, this allows women to freeze their healthy eggs, to prevent the chosen eggs from aging normally. 

When the woman feels ready for a pregnancy, she can then use her preserved eggs to ensure a healthier pregnancy. This helps ease her concerns of chromosomal abnormalities which otherwise increase with her age, especially once she crosses the age of 35.

Use of Frozen Eggs in IVF

The process of combining a woman’s egg and a man’s sperm in a laboratory setting is called “In vitro fertilization” or IVF. ‘In vitro’, means ‘outside the body’. Unfertilized eggs are first harvested from the woman’s ovaries. They can be used for her immediate fertility requirements or frozen and stored for later use. 

At any desired time in the future, any of these frozen eggs can be thawed and then combined with sperm in the lab. If all goes well, and the egg gets fertilized, the resulting embryo is then implanted in the uterus of the woman.

Sometimes if a woman using IVF is able to conceive a child using this technique, she can choose to freeze the remaining harvested eggs for later use, for when she wants to have another child. She can also choose to donate her frozen eggs to other women who are struggling to conceive. IVF using frozen donor eggs are said to have the highest success rates among all kinds of fertility treatments. The U.S. Centers for Disease Control and Prevention revealed that around 12% of the total  IVF cycles/year in the U.S, (approx. 16,000) involve eggs that are retrieved from egg-donors.

Why Egg Freezing Works

There are two primary reasons why egg freezing is effective in helping women get pregnant:

  • As mentioned earlier, as a woman ages, her eggs age along with her. Younger eggs are more likely to be genetically normal while older the egg, the higher the chances of genetic abnormality. So, as a woman grows older, her percentage of genetically normal, healthy eggs reduces dramatically. 

This decline in her egg quality is a natural and inevitable occurrence. Freezing her eggs while she’s still young allows these eggs to avoid the damage that comes with age, and this helps increase her chances of having the healthiest baby possible, at any later age.

  • The second reason why egg-freezing is an effective way to extend your childbearing years is that the process of freezing and thawing eggs has no drawbacks in comparison to the effectiveness of fresh eggs used during in vitro fertilization. Studies conducted with an emphasis on this comparison have concluded that that frozen and thawed eggs are not inferior to fresh ones in any way. 
  • A 2010 randomized controlled study observed 600 women undergoing IVF, using eggs from egg-donors. Half of them used recently retrieved, never frozen, fresh eggs while the remaining women used frozen and thawed eggs. The researchers found that pregnancy success rates were more or less the same in both groups.

In other words, if a woman freezes her eggs at the age of 30 and wants to thaw them for use at the age of 40, then her chances of achieving pregnancy using those eggs in an in vitro fertilization cycle would approximately be the same as the time she froze these eggs. Egg freezing success rates directly correspond to the women’s age at which the eggs were frozen, effectively pausing her fertility clock at this point in time.

How Egg-Freezing Works: Ovarian Stimulation

The technique of Egg Freezing requires three primary steps which start with ovarian stimulation, then the egg retrieval and finally, the freezing.

Ovarian Stimulation: Typically, only one egg develops monthly. To stimulate your ovaries to produce multiple eggs, you have to take synthetic hormones. This may include injections of menotropins, follitropin alfa or beta, etc.

You may also need to take medications to prevent premature ovulation such as an injectable gonadotropin-releasing hormone agonist (leuproline acetate) or a gonadotropin-releasing hormone antagonist (cetrorelix).

Blood tests are conducted to measure the effectiveness of  ovarian-stimulation medications. If the follicles are developing then estrogen levels will increase while progesterone levels start rising only after ovulation. Your doctor will continue to monitor your progress and will probably use vaginal ultrasounds to study the development of fluid-filled sacs (follicles) where eggs mature. 

It takes about 10 to 14 days for the follicles to be ready for egg retrieval. At this point, your doctor may give you an injection of human chorionic gonadotropin to help the eggs mature.

Egg Retrieval

Transvaginal ultrasound aspiration is the common method used for Egg retrieval. This procedure is performed at the doctor’s office or clinic. You will be sedated and an ultrasound probe is inserted in the vagina for identifying the mature egg follicles. 

A needle with a suction device is then guided into the vagina to remove the eggs from the follicles. The more the eggs removed, the better the chances of getting pregnant. Up to 15 eggs per cycle can be retrieved. Once the procedure is over, you may experience abdominal cramping. Your ovaries may remain enlarged for a few weeks and you may feel a sensation of fullness or pressure in that region.

Freezing Retrieved Eggs

Once your unfertilized eggs have been harvested, they are preserved for future use by cooling them to subzero temperatures. Using frozen unfertilized eggs offers higher chances of a successful pregnancy than using frozen fertilized eggs (embryo).

Vitrification, a flash-freezing technique, is the most commonly used process for egg freezing. Cryoprotectants are used in this rapid cooling process to help prevent ice crystals from forming. Slow freezing is the other technique used for egg freezing. But vitrification is considered to be a  more effective technique since this reduces the risks of damage to the eggs, ensuring higher rates of egg survival during the freezing and thawing.

Cryotec vitrification is one of the best cryopreservation methods as this has a near 100% egg survival rate. Keep in mind that a 100% egg survival rate is not the same as saying all these will get fertilized and lead to pregnancies. But successful egg freezing ensures that you get the best start possible when want to delay having a child till you feel ready for it.

The Final Results

When you feel ready to be a mom and decide to get pregnant, you can now use your frozen eggs. They will be thawed and fertilized with sperm in the lab and the resulting embryo is implanted in your uterus or that of a chosen gestational carrier. 

To fertilize the egg, a single healthy sperm is usually injected directly into each mature egg using a technique called intracytoplasmic sperm injection (ICSI). Depending on your age at the time of egg retrieval and freezing, your chances of becoming pregnant using frozen eggs are about 30 to 60%. 

It’s important to freeze your eggs before you get older than the desired age range as the older you are at the time of egg freezing the lower your chances of a successful pregnancy using these frozen eggs, it’s best to freeze your eggs in your twenties or maximum by early thirties, to increase the likelihood of storing healthy eggs. Once frozen, you will have effectively stopped your biological clock and these eggs can be stored indefinitely till you want to start the clock again.

If you are considering freezing your eggs, there are certain factors you need to take into consideration. To determine whether egg freezing is appropriate for you, your doctor may recommend that you first do a fertility test to determine your ovarian reserve. To understand how to get started with Egg freezing or what to do next, read our next article in this series: Is Egg Freezing Right For Me?

References:

https://www.itv.com/news/2017-05-26/mother-who-beat-cancer-tells-of-miracle-of-worlds-oldest-frozen-egg-baby/

https://www.ncbi.nlm.nih.gov/pubmed/29223749

https://www.ncbi.nlm.nih.gov/pubmed/29480938

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4467930/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5590714/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6262467/

https://www.ncbi.nlm.nih.gov/pubmed/29121511

http://obgyn.ucla.edu/egg-freezing

https://www.hfea.gov.uk/treatments/fertility-preservation/egg-freezing/

https://en.wikipedia.org/wiki/Oocyte_cryopreservation

https://www.medicalnewstoday.com/articles/314662.php

 

 



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