Frozen Donor Embryos in Canada

A new freezing technique has largely replaced traditional slow freezing and has led to vastly improved thaw survival and success rates, now equaling fresh cycles. Vitrification is the flash freezing of embryos or eggs which leads to none of the cell damage and crystallization present in traditional slow freezing techniques. With vitrification, the water is removed from the egg cell and replaced with another agent, then cooled in liquid nitrogen at high speed. When vitrified embryos are warmed, average survival rates are now around 98%, and average survival rates for warmed oocytes (eggs) with this new technology are now between 90% and 95%

It is for this reason that The American Society for Reproductive Medicine (ASRM) and The Society for Assisted Reproductive Technology (SART), in 2012, removed egg freezing from the list of experimental procedures. Multiple studies have concluded that there is no significant difference in fertilization rates, implantation rates, or pregnancy rates between vitrified eggs and fresh eggs. It is this scientific advancement in assisted reproduction that has led to our ability to create our industry leading donor egg bank

Frozen Donor Eggs Vs Fresh Donor Eggs Statistics

According to the American Society for Reproductive Medicine, the foremost authority in the world in reproductive medicine, recent studies suggest the following comparison between frozen (vitrified) and fresh donor eggs used in IVF:

1. 74.2% of frozen eggs vs 73.3% of fresh eggs successfully fertilize
2. 39.9% implantation rate with frozen eggs vs 40.9% implantation rate with fresh eggs
3. 55.4% pregnancy rate with frozen eggs vs 55.6% pregnancy rate with fresh eggs used in donor cycles

It is this technology which is rapidly changing the landscape of third party egg donation in assisted reproduction from the use of fresh donor eggs to frozen donor eggs.

Egg Donor Genetic Carrier Screening

Intended parents’ biggest desire is to have a healthy child. We live in an amazing age with rapid advances in science and genetics which allows for the pre-donation genetic assessment of all of our egg donors. Our egg donor testing is some of the most advanced in the business, and we follow the recommendations of the American Congress of Obstetricians and Gynecologists and the American College of Medical Geneticists and Genomics. It is designed to detect genetic mutations associated with a number of hereditary disorders with greater than 99.9% accuracy. It is conducted by the acquisition of blood or saliva from the egg donor. Unfortunately, our testing does not and cannot detect every genetic disease, but it goes a long way to reducing risk.

All our donors undergo advanced genetic carrier screening before being selected. Many people are carriers of genes associated with hereditary genetic diseases but they have no impact on their lives. If both partners are carriers of the same gene mutation (autosomal recessive inheritance), there is a higher risk that the conditions can be passed on to a child, and many are clinically significant.

Certain populations are more likely to have certain gene mutations such as: Ashkenazi Jewish, African American, and French Canadian. As all our donors are fully screened and the results available, sperm donors are encouraged to have testing as well to assess the risk of autosomal recessive conditions being passed on to the child. Our testing facilities have genetic counselors who can do risk evaluations after testing has been completed.

It is important to remember that in most cases both the egg donor and the sperm donor must be carriers of the same genetic mutation in order for it have a statistical chance of presenting itself in offspring. In most cases, if both partners are carriers of the same genetic condition, 25% of fetuses will be affected, 50% will be carriers of the genetic mutation, and 25% will not be carriers of the defect. In some cases like Fragile X, it is passed soley through the X chromosome, and females have a 50% of passing on the mutation. We typically test for the following conditions, although testing can vary on donors:

1. Cystic Fibrosis
2. Tay-Sachs Disease
3. Sickle Cell Disease
4. Fragile X Syndrome
5. Beta Thalassemia
6. Alpha Thalassemia
7. Bloom Syndrome
8. Canavan Disease
9. Familial Dysautonomia
10. Fanconi Anemia Type C
11. Gaucher Disease
12. Mucolipidosis IV
13. Niemann-Pick Disease
14. Spinal Muscular Atrophy