There are many tests that one can undergo when pregnancy to ensure the health of the pregnant person and the health of the baby.
For most pregnant people, it is simplest to go with the flow and have the tests the doctor recommends and trust that your doctor will let you know the results and help you navigate any decisions that need to be made. Prenatal testing can feel more daunting for Intended Parents. Most Intended Parents are not able to attend each doctor’s appointment or test, so they can miss out the discussions with the doctor. Because Surrogate Mothers have gone through these tests before, they may not seem like a big deal but for Intended Parents in another city or country, it can be kind of scary.
Throughout the IVF and surrogacy process, there will be many tests, both routine and optional.
Testing Prior to Pregnancy
When using your own sperm, you can expect that the semen will be tested. Eggs can also be tested for quality. Donor eggs are not usually tested because the risk of genetic abnormality for women under 30 is very small and most egg donors are under the age of 30.
Once embryos are created there are two types of testing available. PDG or preimplantation genetic diagnosis, is a test where a cell is taken from an embryo for genetic testing prior to an embryo transfer. PDG is used to test for a specific genetic condition such as cystic fibrosis. PDG is also the term used by most people to describe PGS testing, too.
PGS testing or preimplantation genetic screening is the correct term for embryo testing that looks at the overall normalcy of an embryo’s chromosomes.
PDG and PGS are not 100% accurate. Embryos that may result in a healthy baby can be shown as possibly abnormal and embryos that pass screening may still result in pregnancy loss due to abnormal chromosomal count.
In fact, it is important to note that none of the screening tests available to you are 100% accurate. Tests like amniocentesis and The Harmony Test have higher accuracy rates of 98-99% are still not perfect. We will talk more about these tests in turn.
Once your embryos are ready to be transferred and a pregnancy is achieved, prenatal testing begins.
At as early as 10 weeks you can choose to have The Harmony Test done. The Harmony Test is a test you must order and invest in privately. When pregnant, a person’s blood contains fragments of the fetus’s DNA. The Harmony Test looks at this DNA to test for Trisomy 21 (Down’s Syndrome), Trisomy 18 (Edwards Syndrome) and Trisomy 13 (Patau Syndrome).
The Harmony Test can be used people of any age or risk factor. It has a very high accuracy rate of over 99% with a false positive rate of 0.1%.
Nuchal Translucency (NT) Ultrasound
Between 10 and 13 weeks a routine ultrasound is usually performed. This is called the NT scan. This ultrasound also helps to confirm the estimated due date (but obviously in IVF that is less relevant).
Nuchal translucency is a pocket of fluid on the back of the fetus’s’ neck. All babies have some fluid in the area but babies with Down’s Syndrome may have more fluid.
On its own an NT scan can not tell you if your baby has Down’s Syndrome but combines with blood tests it can help you decide whether or not to undergo more invasive screening such as CVS (Chorionic Villis Sampling) or Amniocentesis. These tests are far more accurate but do carry a risk of miscarriage.
CVS (Chorionic Villis Sampling)
CVS tests cells from the placenta to look for chromosomal abnormalities. The procedure is guided by ultrasound and provides faster results than amniocentesis. This can be done two ways:
Transcervical: A catheter is guided through the cervix to the placenta where a small sample is taken.
Transabdominal: Like amniocentesis, a needle is inserted through the abdomen to collect the sample from the placenta.
With the guidance of ultrasound, a needle is inserted into the abdomen and amniotic fluid is collected and then tested for chromosomal abnormalities. Unlike CVS, amniocentesis can also check for neural tube defects.
If you’re having trouble deciding which screening tests are right for you, you may want to check out Genetic Testing: Is Safe Always Better Than Sorry?