Recently announced results of a newly released IVF study shows that delaying embryonic screening for chromosomal abnormalities until the fifth day of development – the blastocyst stage – significantly improved implantation rates and led to more successful pregnancies. The study was published online in the June edition of Fertility & Sterility.
While many IVF patients choose to have their embryos screened for chromosomal viability, testing has traditionally been conducted on day three, at the cleavage stage of development. Data from the new study shows that the practice of cleavage-stage biopsy can impair an embryo’s ability to implant and become a healthy pregnancy and delivery.
At the blastocyst stage, the fifth or sixth day of development, the embryo consists of about 200 cells. Testing at this point is much safer, as cells are taken only from the portion of the embryo destined to form the placenta, called the trophectoderm. These cells reveal the same genetic information contained within the cells that will eventually form the fetus while allowing the physician to leave the fetal cells untouched and uncompromised.
By contrast, at the cleavage stage, an embryo is made up of six to eight cells, which means that traditional testing at this point in development has required the removal of up to one-sixth of the embryo’s total volume.
It’s critical that embryo biopsy for genetic testing is done at the blastocyst stage to improve both safety and outcomes for patients. This applies to screen for both single-gene abnormalities as well as aneuploidy, which is an abnormal number of chromosomes. It’s also important to note that while time-lapse video imaging platforms have the potential to add to the conventional approach of grading embryos at discrete time points, none has been shown to accurately predict the chromosomal status of embryos. Even embryos that look good and develop in a timely manner may have a high risk of being chromosomally abnormal and result in an unsuccessful IVF cycle or a miscarriage.
The combination of blastocyst biopsy with comprehensive chromosome screening provides both increased safety and chance for success.
RMA Genetics pioneered SelectCCS as the new standard of care for infertility patients. This one-of-a-kind 24-chromosome screening platform identifies whether embryos are euploid (normal number of chromosomes) or aneuploid (abnormal number of chromosomes), enabling the selection of only the healthiest embryo for transfer.
Used in combination, SelectCCS with Single Embryo Transfer (SET) can help to make “one embryo, one baby” a reality for patients undergoing IVF, providing uncompromising success rates without complications often associated with twin pregnancies and deliveries.