It might sound daunting to have your and your partner’s genetic makeup and quality tested; it can feel like it’s just another thing to tack onto your long list of worries and concerns while dealing with infertility. But while it may seem overwhelming, genetic testing is truly a groundbreaking science that can provide a helpful road map for your doctor to work with on your fertility journey.
So, should you do genetic testing before–or during–IVF? Let's look at the options:
Genetic Carrier Screening
Genetic Carrier Screening is a DNA blood test that determines whether a not a person is at risk for passing certain genetic conditions onto their child(ren). Genetic carrier screening evaluates for conditions that are inherited in either an autosomal recessive or X-chromosome-linked manner. What does this mean? Well, in short, a condition that is autosomal recessive means that both parents would have to be carriers of the same gene in some variation for it to be passed on to their child. An X-chromosome-linked condition means that the woman carries the gene and, therefore, has an increased chance of passing it on to her child, particularly if the child is a boy.
Genetic Carrier Screening is typically done before beginning IVF. Knowing as much about each parent’s genetic makeup as possible allows your fertility specialist to come up with the best reproductive options for you in the event that you, and/or your partner, are carriers of certain genetic conditions.
Karyotype testing can also be referred to as chromosome analysis. This type of blood testing looks at the size, shape, and number of your chromosomes to see if anything about them is unusual.
Your doctor might recommend karyotype testing if you’ve been trying to conceive for more than a year, or if you’ve experienced two or more consecutive miscarriages. In cases of Male Factor Infertility where intracytoplasmic sperm injection, or ICSI, is used, genetic karyotyping will be required beforehand since ICSI-IVF increases the risk of male infertility passing on to the child.
Infertility itself is enough of a hardship; not knowing why you have struggled and experienced such heartbreak adds another layer of pain to it all. Karyotype genetic testing can help answer big questions, such as the cause of recurrent miscarriages. It can also diagnose structural issues within your chromosomes, like a balanced translocation.
A balanced translocation is a condition in which part of a chromosome has broken off and reattached in another location. In other words, it means that sections of two chromosomes have switched places. Many people can have balanced translocation without knowing it, but when that person's cells divide to create egg or sperm cells for reproduction, the egg or sperm cells can end up with extra genetic material or missing genetic material. This could lead to miscarriage depending on which chromosome and genes are affected.
If you or your partner is diagnosed with a balanced translocation through karyotype testing, don’t panic! IVF with PGT-SR testing can help ensure that any embryos you end up transferring are healthy ones.
Preimplantation Genetic Testing (PGT)
Preimplantation genetic testing (PGT) examines embryos created during IVF before they are transferred to a woman’s uterus. PGT looks for a range of possible genetic issues that could cause implantation failure, miscarriage, or birth defects. There are three types of tests that might be done during preimplantation genetic testing: PGT-A, PGT-M, and PGT-SR.
PGT-A testing screens for an abnormal number of chromosomes in the embryo, or aneuploidy. Embryos might have missing or extra chromosomes, which are more like to result in failed implantation or miscarriage. PGT-A testing can help ensure that only euploid, or chromosomally normal, embryos are transferred, and the benefits include increased chances of implantation and pregnancy; reduced risk of miscarriage; reduced number of IVF cycles needed to achieve pregnancy; and increased chances of giving birth to a healthy baby. PGT-A is appropriate for the vast majority of IVF patients but is typically recommended for women over the age of 35, women who have experienced recurrent pregnancy loss, and women who have had a pregnancy with chromosomal abnormalities.
Not just for patients with infertility, PGT-M testing screens for monogenic diseases within the embryo and looks for a singular, specific disease. Whether one partner has a genetic condition that they want to avoid passing on to their child(ren) or both partners carry it, this type of genetic testing can ensure that the genetic disorder is not passed on to the couple’s child(ren), which is pretty amazing.
Lastly, PGT-SR testing screens for structural chromosomal rearrangements, such as inversion or translocation, and can help prevent miscarriage and implantation failure.
Deciding What’s Best for You
Whether you’re struggling with infertility or pregnancy loss, your fertility specialist will most likely recommend some form of genetic testing to help determine the best treatment plan for you. From Genetic Carrier Screening to Karyotype Testing to Pre-Implantation Genetic Testing, the groundbreaking science of genetics has helped countless couples find answers and feel more in control of their reproductive future. There is even some genetic testing you can do at home! Knowledge is power when it comes to the health of your future child(ren), and genetic testing can be one silver lining to needing fertility treatments to grow your family.
Brighid Flynn is a freelance writer based in Philadelphia where she lives with her husband and puppy. She is just beginning her journey toward motherhood.