Pregnancy rates with in vitro fertilization (IVF) have steadily increased over the past decade. However, for many the rates are still not high enough and multiple attempts with IVF or frozen embryos may be required to become pregnant. If pregnancy does occur, the risks of twins or triplets are very high, resulting for some, a high risk pregnancy and delivery. Additionally, the success rates with IVF tend to decline with increasing age of the women. A major cause of miscarriage or a lack of pregnancy with IVF seems to be aneuploidy. Aneuploidy is defined as extra or missing chromosomes in the embryo (fertilized egg). More frequently, this occurs due to an abnormal number of chromosomes in the egg. In fact, more than half of the embryos obtained from women in their 30s and early 40s may have aneuploidy.
Comprehensive chromosomal screening (CCS) is a type of preimplantation genetic screening that is offered at the Center for Advanced Reproductive Medicine and Fertility. CCS allows screening of embryos for aneuploidy prior to embryo transfer. Only embryos from a pool of embryos with normal appearing chromosomes are selected for transfer. This appears to increase the IVF pregnancy rates tremendously, even for older women, and also results in high pregnancy rates from a single embryo transfer (SET). SET is preferable since it reduces the chances of twins or triplets with the IVF cycle.