Plan B: Embryologist Constantinos Pavlides about Egg Freezing

Elective oocyte cryopreservation (egg freezing) is increasing in numbers as more and more women delay motherhood. With egg freezing, women may extend and ‘secure’ their fertility for the years to come, but most importantly this must be done wisely.

It is well accepted that women’s fertility declines after the age of 35 and reaches 1-2% by the mid-40s; the ovarian reserve is reduced at this age as well. Therefore, women should undergo appropriate counseling, and testing before deciding to preserve their fertility by freezing their eggs.

What is the best age to freeze your eggs?

Younger women (<35 y/o) will freeze more and better-quality eggs; just like when using fresh eggs in IVF. The oocyte quality decreases with time; chromosomal abnormalities increase in women’s eggs from age 35 onwards. Therefore, age is directly related to the pregnancy rate.

What does egg freezing involve?

Egg freezing is an IVF process that takes up to three weeks to complete and involves controlled ovarian stimulation therapy (hormonal medications to produce more eggs per cycle). Every woman is unique and different stimulation protocols could be used for stimulating the ovaries; however, we always aim to collect enough eggs to have a good chance to achieve a pregnancy in future treatments. 

It was estimated that a number of around 20 eggs in the age group younger than 38 could lead to 75% delivery of at least 1 child (Doyle et al.2016). Women between 38-40 will need a higher number of eggs, 25-30 to reach this rate, whereas the 40+ group will need a number close to 60 oocytes to reach that rate. 

Taking into consideration similar studies, it is clear here that age is the main factor for success. To achieve these numbers, a patient may require to undergo more than one egg freezing cycle. More eggs collected result in higher chances of achieving pregnancy later. 

How successful is egg freezing?

Using frozen eggs is well established and thousands of healthy babies were born worldwide. However, it is important to mention that: 

  •  Not all oocytes will produce viable embryos at the end. Like in IVF cycles using fresh oocytes, we may have oocytes that are not fertilized, embryos that do not grow normally and do not reach the desirable blastocyst stage. In some cases, oocytes of lower quality may show a higher degeneration rate than what we normally expect due to the sensitivity of their cell membranes
  • Not all embryos created will lead to a pregnancy and delivery. Similarly to fresh IVF cycles, there is no guarantee that a perfect blastocyst will implant. Factors such as endometrial receptivity, embryonic genome, lifestyle factors, and age may impair implantation 
  • Experienced laboratories may have better results with frozen eggs. Egg vitrification is a delegate procedure. Not all embryologists will achieve the same high survival rates. The experience and skills of the performing team with a proven history of egg freezing and thawing of oocytes will have an impact on the outcome of such a treatment. The first step of the process involves freezing the oocytes, but it is equally essential that they remain viable when it comes time to use them, with the potential to develop into high-quality embryos that can lead to a successful pregnancy.
  • A woman’s general health and lifestyle are directly related to her egg quality. It has been shown that substance use, including tobacco, marijuana, heavy drinking, and using illegal drugs like heroin and cocaine reduce fertility both in women and men. In obese women, with PCOS, losing 5% of body weight improved the likelihood of ovulation and pregnancy. Ongoing research also shows that exposure to persistent organic pollutants and endocrine-disrupting chemicals (EDCs) in the environment can also affect male and female fertility (National Institute of Child Health and Human Development; NIH).

How long can the frozen eggs be stored?

The storage period in Cyprus is 10 years with the option to extend that period if needed.

How to choose a clinic for egg freezing?

It is important to choose a clinic that has a history of egg vitrification with proven results. Freezing oocytes is the first part of the procedure; the oocytes should also survive when you finally need to use them and have the potential to create good embryos for achieving a pregnancy. Pedieos IVF Center has been incorporating egg vitrification into our routine practice since 2008, amounting to 15 years of experience. Notably, our results in this field were published in the Fertility and Sterility Scientific Journal in 2011.

I would like to highlight that citizens of Cyprus who are 35 years old or above have the opportunity to apply for a sponsorship of €2,000 for Oocyte Cryopreservation. Additionally, younger patients with valid medical reasons may also be eligible to benefit from this program. Our team has assisted numerous women in taking advantage of this scheme, and I invite anyone considering egg freezing to contact us for further information and assistance.

15 years ago, women didn’t have a choice to delay their motherhood. Now, this opportunity exists. Even though fertility preservation is becoming more and more popular, there are still people who are not fully aware of such an option or have limited information. It is important to raise awareness of the benefits and best practices of egg freezing. For some, it can be a life-changing opportunity.

About Constantinos Pavlides

Constantinos Pavlides studied in Greece and received his BSc Degree in Biology from the University of Crete in 2003. He further continued his studies in embryology and achieved the MSc from Nottingham University, UK (Master of Medical Science in Assisted Reproduction Technology). He is currently working as a Lab Director & Head Embryologist at Pedieos IVF Center with special interests in oocyte vitrification, Frozen Embryo Transfer, and Preimplantation Embryo Biopsy.

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