Navigating Genetic Testing in Surrogacy

Navigating the complexities of surrogacy involves careful consideration of the health of both the surrogate mother and the baby. In this guide, we explore various genetic tests, with a focus on the common concerns surrounding Down syndrome and the decision-making process for intended parents and surrogates.

Genetic Tests and Surrogacy

Intended parents usually ask if they need to request their surrogate gets an amniocentesis if Preimplantation Genetic Screening (PGS) has been done, and understanding the types of genetic problems affecting human chromosomes is crucial in surrogacy.

Although many types of genetic problems can affect human chromosomes, the main concern is Down syndrome (trisomy 21) because it’s the most common genetic abnormality for babies born around the world.

The risk of chromosomal anomalies (such as Down syndrome) increases with the age of the genetic mother (or egg donor). Typically, using a young egg donor, the risk is already relatively low, and adding a normal nuchal result makes the risks even lower, typically less than 1:10,000.

Role of Preimplantation Genetic Screening (PGS)

PGS serves as a tool to reduce the risk of chromosomal anomalies, including Down syndrome. However, before deciding, you must know that PGS is a tool to reduce risk, not eliminate it.

The scientific literature reports accuracy as high as 98%. Under clinical conditions, accuracy could be lower for random chromosome abnormalities. In general, it’s recommended that you should follow up prenatal testing to confirm these findings; what options do you have?

Prenatal Genetic Tests

Several genetic tests can done during the pregnancy process to screen for Down syndrome and other chromosome problems: those done on the egg donor, on the Intended Parents (screening for recessive genetic conditions), on the embryo pre-implantation (PGS or PGD), and tests targeted at the developing embryo/fetus once pregnancy has been achieved.

The most common screening test for chromosome abnormalities is based on an ultrasound and/or a blood test, which doesn’t involve any risk of miscarriage.

The Nuchal Translucency test is performed at about 12-13 weeks and is accompanied by a blood test. This test can detect up to 91% of T21 fetuses. Usually, if the ultrasound (or the blood test) shows an increased risk of chromosome anomaly, an amniocentesis is prescribed.

Amniocentesis and Alternatives

Two invasive diagnostic techniques have been made available to women, particularly those above the age of 35, to detect these problems. These tests are called chorionic villus sampling (CVS) and amniocentesis. They are referred to as diagnostic tests because they can diagnose Down syndrome with 100% accuracy but are “invasive” because there is a small risk that the procedure (which involves a needle that traverses the uterus) will lead to a miscarriage, at a frequency of about 1 for 200-500 procedures performed.

However, some Intended Parents refuse amniocentesis because they would choose to keep the child regardless of the result. Are there any other alternatives available?

In recent years, a new family of tests has been developed: the cell-free DNA tests or non-invasive prenatal screening commercially known as Harmony, MaterniT21, Verify Panorama, and others.

In general, these tests cannot only detect over 99% of cases of Down syndrome with a false positive rate of less than 1%. Please note that some of those tests cannot be used in a pregnancy where an egg donor is involved.

PGS and surrogacy

Conclusion

Whether you decide to become a surrogate or an intended parent, before matching, there must be an honest discussion between the surrogate and IPs about their feelings on invasive diagnostic tests like amniocentesis, selective reduction, or abortion to ensure that they are on the same page.

Also, remember to have an in-depth discussion and determine the medical and social circumstances under which both parties would agree to reduce or terminate a pregnancy.

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Written by David
I work daily to make surrogacy available to as many intended parents, surrogate mothers and egg donors around the world as possible.

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