Understanding the usefulness of genetic screening
Genetic screening is a specialized laboratory test helpful in detecting genetic defects or chromosome disorders. Clinics can use genetic screening to determine the optimal embryo to use during the IVF process. Tests like PGD, PGS, and CCS are processes available at advanced IVF clinics. Each test provides different outcomes. So which test is the best option?
Fighting defects with PGD
Preimplantation genetic diagnosis (PGD) allows a lab to sample genetic material from an embryo and check for anomalies. The test is helpful when there is a known single gene defect like cystic fibrosis or sickle cell anemia. Some added reasons include age, a history of miscarriages or infertility. By removing the embryos with defects, PGD improves the chances of a successful IVF cycle.
Detecting rogue chromosomes with PGS
PGS takes PGD to the next level. The preimplantation genetic screening (PGS) test seeks out chromosomal defects, also known as aneuploidy. An embryo may have more or less than the 46 chromosomes present in humans. This phenomenon is the cause of Down syndrome or Turner syndrome. Embryos with this trait very rarely last full-term. By screening both sperm and egg, PGS improves successful fertilization. PGS can also get to the root cause of infertility.
CCS covers all the bases
The advancement in technology has allowed PGS to graduate to comprehensive chromosome screening (CCS). CCS tests all 23 pairs of chromosomes. Previous versions of PGS allowed the testing of only 9 pairs. Because PGS has been gradually replaced by CCS, people often use the terms PGS and CCS interchangeably. While all the tests aren’t perfect, the success rates without screening are noticeable. For example, studies show increased birth rates and decreased miscarriages in women over 35 who opt for these screenings.
The detailed PGD and PGS process
The IVF clinic extracts eggs from the ovaries after the woman goes on a course of hormones. The clinic fertilizes the eggs with the sperm. Once the embryos reach 5 days, genetic material harvested from the embryos goes to a lab for testing. At this point, the clinic freezes the embryos. The lab will then test the sample for hundreds of known and unknown defects, including aneuploidy. With PGS, the ICSI and IVF process creates an embryo with exactly 46 chromosomes useful for genetic screening.
After the test
With the results back to the clinic, the patient and physician review the results. The clinic keeps and thaws the best embryo on the day of IVF implantation. The clinic also keeps the best embryos for future IVF cycles if necessary. Clinics providing PGD and PGS have the advantage of implanting one embryo per cycle. This reduces the chance of multiple births and miscarriages. PGD extends the process of IVF as testing takes a further 1-2 weeks. Patients should keep this timeframe in mind.
Screening reduces stress
Couples should consult with a fertility specialist to find out the best genetic screening available. The tests require very skilled medical practitioners and labs. As the process constantly changes, clinics must stay ahead of the curve to provide patients with the best genetic screening. Tests reduce the chances of miscarriage, requiring fewer IVF cycles. Based on genetics, choosing the best screening option makes the IVF process smoother.
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