Genetic Screening for Chromosome Anomalies
Cleveland Clinic is offering a new technique for screening patient embryos and selecting those most likely to result in a pregnancy. This powerful new technique know as Trophectoderm Biopsy allows the removal of multiple cells at the blastocyst stage. Embryos can be examined for inherited genetic disorders as well as chromosomal abnormalities. Patients with recurrent losses or at risk for chromosomal abnormalities can have their embryos analyzed using the new Genesis-24 screen. By testing a patient’s embryos for chromosomal abnormalities and selecting only normal embryos for transfer, the patient's opportunity for a pregnancy with a healthy baby is increased. The Genesis-24 technique is quite powerful and allows transfer of embryos in the same IVF cycle.
New Freezing Technique Offers Benefits to In Vitro Fertilization Patients
A new freezing technique known as vitrification allows oocytes and embryos to be “flash” frozen. Cleveland Clinic's IVF laboratory has been a pioneer in using this technology for freezing of embryos at the 6-8 cell stage. We published the first paper in the U.S. with live birth and outcome data from transfer of cleavage stage embryos frozen with this new methodology.
What does cryopreservation involve?
Cryopreservation traditionally has involved:
- The use of cryoprotectant solutions
- Dehydrating the cells
- A very slow cooling process, followed by plunging the embryos into liquid nitrogen.
Problems with conventional slow freezing methods for cryopreservation:
- Freezing process almost two hours, which increases the chance for intracellular ice crystal formation, potentially causing cell damage when the embryos are thawed.
- Less successful for freezing eggs due to their size and sensitivity of chromosomes on meiotic spindle to temperature change and ice crystal damage.
Vitrification, has shown tremendous promise in increasing the survival rates of both embryos and eggs after cryopreservation.
How does vitrification work?
Vitrification involves rapid freezing of eggs and embryos at rates of -15,000º C in high concentrations of cryoprotectant. This is achieved by placing the cell in very miniscule fluid volumes of less than one microliter and using very special vessels for the freezing. This technique transitions the eggs or embryos quickly into a “glass-like state,” minimizing the potential for ice crystal formation during the freezing process.
What are advantages of vitrification?
Advantages of vitrification include:
- Increased successful pregnancy outcomes
- Expands fertility preservation to include egg freezing
- Increase cumulative pregnancy rate from a single egg retrieval
- Can be used as an adjunct to embryo freezing to reduce number of embryos frozen.
What are the specific benefits of egg freezing?
The benefits of egg freezing include:
- Egg cryopreservation, as an alternative to embryo preservation, has the potential to resolve ethical issues that can occur when couples who have undergone IVF become pregnant and struggle with excess embryos they may no longer need.
- For young women undergoing chemo or radiation treatment for cancer, this technology provides an opportunity to preserve fertility by banking their eggs.
Vitrification has greatly improved outcomes with egg cryopreservation. However, unlike embryo freezing which is universally accepted, successful egg freezing is still in its infancy. Patients interested in egg freezing can participate in an ongoing research study at Cleveland Clinic.
What are the success rates of embryo vitrification?
Embryo vitrification has significantly improved clinical pregnancy and live birth rates in Cleveland Clinic’s IVF program.
We now exclusively use this technique for cryopreservation of human embryos at all stages. The IVF laboratory and its associated research labs continue to work on cutting edge technology to help advance the field of cryopreservation.
For More Information
For more information about cryopreservation at Cleveland Clinic, call 216.839.3150. We have Cleveland Clinic Fertility Center offices at Beachwood, Cleveland Clinic main campus, as well as our family health centers in Avon, Solon, Strongsville and Twinsburg.