Genetic Testing Improves IVF Success
There is no guarantee that an in vitro fertilization cycle (IVF) cycle will be successful – resulting in a pregnancy or live birth. Most IVF cycles that fail are because of random genetic abnormalities in the embryo(s).
Inefficiencies in reproduction
Unfortunately human reproduction is fairly inefficient, and the older we get, it becomes even more inefficient.
Since the inception of IVF in the early 1980’s, we have worked diligently to combat these inefficiencies and there have been many advances that have led to higher pregnancy rates. Arguably, none have been as groundbreaking as preimplantation genetic testing.
Preimplantation genetic testing comes in two forms:
- Preimplantation Genetic Screening (PGS)
- Preimplantation Genetic Diagnosis (PGD)
IVF and genetic testing
With either procedure, a couple goes through a standard IVF cycles where eggs are retrieved and sperm is obtained. Embryos are created and then cultured to the blastocyst stage. That process takes five days.
On the 5th day, an embryo biopsy is performed. A few cells are removed from the portion of the embryo destined to become placenta. The cells are sent for genetic testing and the embryos are frozen, awaiting the genetic report and then a frozen embryo transfer.
How PGS helps with success
PGS is used when a couple wants to screen their embryos for random genetic events – the genetic errors that can cause IVF to fail. These are genetic problems with the embryo that don’t have to do with the parents’ age, and again, are believed to be the number one reason an IVF cycle would not work.
If you can determine which embryos are genetically normal (known as “euploid”), a couple is able to increase their odds of success and minimize their chances of miscarriage. Although success rates will vary from patient to patient and clinic to clinic, pregnancy rates generally increase by 15-20 percent after PGS.
Screening for significant errors
But genetic testing can do more than pinpoint these random genetic errors. We can also perform PGD for specific genetic mutations, such as cystic fibrosis or spinal muscular atrophy. These are abnormalities in an individual’s DNA that predispose his or her children to a specific disease.
These disease mutations can be dominant, where a single gene carried by one parent results in clinical disease, or recessive, where both parents have to carry the genetic mutation and pass it on to their child.
In the case of a dominant inheritance pattern, there’s a 50 percent chance their offspring will have clinical disease. With a recessive pattern, there’s a 25 percent chance the offspring will have clinical disease, while half will be carriers.
PGD should be considered when an individual has been diagnosed with a hereditary disease, had a child diagnosed with a hereditary disease, has family members with a hereditary disease, or both partners have been diagnosed as carriers of a specific hereditary disease.
Screening parents first
How can you know if you and your partner are both disease carriers? There are genetic screening panels commercially available and can be ordered by your provider. At Methodist Reproductive Health Specialists, all our patients are offered carrier screening at their first visit. Carrier testing is optional, but encouraged.
As they say, information is power!