Comprehensive Chromosome Screening

New methods of pre-implantation genetic screening (PGS) provide an opportunity to identify chromosomally normal embryos for transfer in in-vitro fertilization (IVF) cycles. Among the many improvements to historical methods of PGS, new technology provides information for the normalcy of all 24 chromosomes, and has been termed comprehensive chromosome screening (CCS).

Unlike previous methods, CCS prevents the selection and transfer of abnormal embryos for unscreened chromosomes and has powerful evidence of improving IVF outcomes.

The ability to screen all 24 chromosomes from a single biopsy has been made possible through the development of a variety of DNA amplification methods. CCS is used to analyze, select and transfer only embryos that have the appropriate number of chromosomes.

The purpose of screening embryos in advance is to help accomplish higher implantation rates and fewer pregnancy losses. This service is performed particularly for women 35 or older, couples with multiple-failed IVF cycles or implantation failure, and couples with repeated miscarriages. A large number of early miscarriages are related to chromosomal abnormalities in the fetus.

CCS is performed on a few cells biopsied from a patient’s blastocyst. The genetic material of the embryo is not altered in any way during CCS. During CCS, we obtain a few cells on a day 5 or 6 embryo called a blastocyst. Biopsying the embryo at a more advanced cell stage dramatically increases the accuracy of this testing and safety of the embryo because it has several hundred cells by then.

Another advantage to CCS is that we can greatly reduce the odds of a couple having multiple pregnancies (twins or triplets).

It arms clinicians with the knowledge that they are transferring the most chromosomally fit embryo(s), therefore precluding the need to transfer multiple, unscreened embryos in the hope that one will be healthy enough to create an ongoing pregnancy and a healthy baby.