11 Jul Genetic Testing for a Healthy Baby
Genetic testing at various phases throughout conception and pregnancy increases your chances of experiencing a healthy, full-term birth. Chromosomal and genetic abnormalities are the leading causes of failed conception, miscarriage, and failed fertility treatments.
The more information we have about your genetic information, and that of your fertilized embryos, the smarter choices we can make about your fertility future.
It Starts With Preconception (Carrier) Genetic Screening
Preconception genetic screening is done with a simple blood test. Also referred to as prepregnancy or carrier screening, we start by taking a blood sample from the mother and analyzing her DNA for genetic disorders.
We begin with an analysis of the mother’s DNA first for two reasons. First, most birth defects and medical disorders are recessive, meaning both the mother and father must carry the gene for it to pass on to their children. Also, there are some disorders (called X-linked disorders) that are passed down from the mother.
If the mother carries a recessive gene for any disorders screened for, we’ll request a sample from the father to identify whether he is a carrier. If both parents test positive for a particular genetic disease, there is a 25% (1 in 4) chance their child will have it. Genetic information shapes the next steps. This might mean using PGD for conceived embryos, or some couples opt to use donor sperm, donor eggs, or donor embryos instead of their own.
Which disorders are found using pre-pregnancy screening?
Once we have your results, we can tell you whether or not your children are at risk and the chances that they would inherit a particular disorder.
Most basic prepregnancy screening panels are covered by health insurance carriers and test for:
- Cystic Fibrosis
- Spinal Muscular Atrophy
- Tay-Sachs disease
- Sickle cell anemia
- Fragile X Syndrome
- Duchenne Muscular Dystrophy
These are the most common genetic disorders. If requested, patients can pay out of pocket for more comprehensive genetic screening panels, which can screen for up to 500 clinically relevant genetic disorders.
Depending on your reproductive history, your fertility specialist can discuss which option is best for you. For example, if you have had a clear pre-pregnancy panel run but experienced repeat miscarriages or multiple failed IVF cycles, it may make sense to run a comprehensive panel to rule out potential genetic disorders.
After Fertilization: Pre-Implantation Genetic Testing (PGS & PGT)
If you’re pursuing IVF treatment, you have another genetic testing opportunity to optimize your chances of conceiving a healthy baby. There are two options for pre-implantation testing: preimplantation screening (PCS) and pre-implantation genetic diagnosis (PGD). These tests are not typically included in basic IVF costs.
Pre-implantation genetic screening (PGS)
Once your embryo is a handful of cells large, we can biopsy one of those cells and analyze the chromosomes. This analysis is similar to that performed from the mother’s blood sample before you began fertility treatment.
The embryologists performing this work learn:
- The sex of the baby (which is determined by whether the embryo is female-XX or male-XY).
- The number of chromosomes (some genetic disorders are caused by having more, less, or partial chromosomes).
Testing for the number and health of chromosomes is important for couples pursuing IVF because chromosomal abnormalities increase with maternal age. However, more younger couples also choose to participate in PGS to increase their fertility chances.
Pre-implantation genetic testing (PGT)
PGT is similar to pre-conception genetic screening in that the embryos’ cell samples are analyzed for specific genetic disorders.
Originally, PGT was used for couples who knew they had a higher-than-normal risk of passing on a genetic disorder to their children. However, increasing numbers of couples feel it’s worth the investment to use PGT regardless of whether they have or carry a known genetic disorder.
Just because you aren’t carrying a known genetic disorder doesn’t mean your baby won’t have one. Everything from age to environmental factors can compromise the DNA health of both sperm and eggs. PGT is a final layer of caution we can provide, doing our best to ensure only the healthiest embryo is used during your IVF transfer day.
Genetic Testing Results are Not a Guarantee
Patients must understand genetic testing for a healthy baby is not 100% accurate. Results that there is a chromosomal or genetic abnormality are considered reliable. However, embryo testing can’t possibly test for every known condition, so there is no guarantee evaluated embryos that “pass” the test are free of genetic disorders.
Couples should discuss whether or not PGS and/or PGT make sense for their fertility treatment protocol, depending on their family, personal, and fertility medical histories.
FCD Helps Patients Determine Whether Genetic Testing is Right for Them
While we advise all couples to participate in pre-pregnancy genetic testing, we make embryo evaluation recommendations on a case-by-case basis. Contact the Fertility Center of Dallas to learn whether you should consider further genetic testing as part of your fertility treatment plans.