September 2026
Genetic testing in pregnancy is changing quickly. This month, a new set of international recommendations from the International Society of Prenatal Diagnosis (ISPD) and the European Society of Human Genetics (ESHG) was published outlining the use of a type of testing called prenatal genomic sequencing. These recommendations give healthcare providers guidance about when this testing may be useful, what the test can and cannot tell us, and how families should be supported before and after testing.
For families, one message remains especially important: genetic counseling before and after testing is critical. Let’s break down why.
What Is Prenatal Genomic Sequencing?
The authors use genomic sequencing as an umbrella term that includes both exome sequencing and genome sequencing. Briefly, both tests look at DNA for changes in many different genes, but they differ in how much of our DNA they analyze.
Exome sequencing only looks at the parts of our genes that contain instructions for making proteins. These regions, called exons, make up a small portion of our overall DNA. Genome sequencing looks more broadly across nearly all of our DNA, including both the parts that contain instructions for making proteins and other regions of the genome.
Both technologies can help identify genetic changes that may explain certain findings or diagnose a specific condition during a pregnancy.
When Might Prenatal Genomic Sequencing Be Offered?
The new recommendations focus on using prenatal genomic sequencing when there are ultrasound findings that may be explained by a genetic condition. For example, a healthcare provider may offer this testing when:
- An ultrasound shows a difference in the baby’s development that is suspicious of a genetic condition
- An ultrasound shows differences in more than one part of the baby’s body
- A pattern of ultrasound findings may be associated with a genetic condition
- A previous child or pregnancy had certain findings, and similar findings are seen in the current pregnancy
In most cases, prenatal genomic sequencing is considered along with other genetic tests, or only after other testing has been performed without identifying a diagnosis.
Prenatal genomic sequencing during pregnancy also requires a diagnostic procedure, such as a chorionic villus sampling (CVS) or amniocentesis, to obtain the DNA needed for testing. These procedures carry a small risk of complications (such as miscarriage), so families have to consider if they’re comfortable with the associated risks before proceeding with testing.
For additional information about diagnostic procedures and other genetic testing options during pregnancy, see our Pregnancy & Genetics webpage.
Why Might Both Parents Also Have Testing?
When possible, the new recommendations support testing the baby and both biological parents (or egg and sperm source) together. This approach is referred to as trio testing.
Looking at parental DNA can help the laboratory better understand a genetic change found in the baby. For example, they may determine whether a genetic change was inherited from a parent or occurred for the first time in the baby. Information about the parents can also help clarify the potential significance of the genetic change and whether it may explain the ultrasound findings.
What if an Ultrasound Looks Typical?
The new recommendations do not recommend prenatal genomic sequencing for every pregnancy. Instead, they focus on certain situations, such as when ultrasound findings suggest a genetic condition.
If an ultrasound looks typical, it does not mean that a baby cannot have a genetic condition, since some genetic conditions may not cause differences that can be seen with ultrasounds. Instead, it means that there is not enough evidence to recommend prenatal genomic sequencing and that it may be more harmful than helpful.
For example, the criteria used to determine which changes in DNA are likely to be medically meaningful were developed with specific ultrasound findings in mind. Without these findings, it is much more challenging to interpret the significance of genetic results. The authors note that if prenatal genomic sequencing is performed in a seemingly typical pregnancy, stricter criteria should be used for reporting out results.
Why Is Genetic Counseling Important Before and After Testing?
Genetic testing involves more than simply giving a sample and getting a result. Before testing, families should have the chance to understand why the test is being offered, what it may reveal, and what the possible results could mean. This is an important part of informed consent so that families can make a decision that reflects their values, needs, and circumstances.
During pre-test counseling, a genetic counselor can help explain:
- Why the testing is being offered
- What the test can and cannot find
- What other testing options may be available
- What kinds of results might be received, including uncertain results
- How often testing finds a genetic explanation for the ultrasound findings
- Whether the test could find unexpected information (also known as incidental findings)
- How the results could affect the pregnancy and family, including social and emotional considerations
- What the results could mean for future pregnancies
- How the interpretation of results might change over time
- Genetic discrimination and privacy considerations
Genetic counseling is just as important once results are received. Genetic test results can be difficult to understand and a test report may contain unfamiliar medical terms or may not explain the full picture by itself. Results need to be considered alongside ultrasound findings, pregnancy history, family history, and any other test results. Genetic counselors can help connect this information and help families understand what the findings mean and what remains uncertain.
Questions to Ask About Prenatal Genomic Sequencing
If prenatal genomic sequencing has been offered during your pregnancy, you may want to ask:
Before Testing
- Why is this test being offered to me?
- What are you looking for?
- What could the test tell us?
- What can the test not tell us?
- What other testing options are available?
- How long will it take to receive results?
- What types of results could we receive?
- Could we learn something unexpected?
- Will both biological parents be tested?
- What would different possible results mean for my pregnancy?
- What are the financial considerations of this testing?
- Are there any privacy considerations with this testing?
- Will I meet with a genetic counselor before testing?
After Testing
- What does this result mean?
- How certain are we about what this result means?
- How much variability can be seen with this condition?
- Does this result help explain the ultrasound findings?
- What does the result not tell us?
- Should other family members consider genetic testing?
- Could this result affect future pregnancies?
- Should the genetic information be reviewed again in the future?
Bottom Line
These new recommendations recognize that prenatal genomic sequencing can be a useful tool when ultrasound findings may be suggestive of a genetic condition. However, genetic testing is not right for every pregnancy, and more testing does not always mean more answers.
Whether testing is appropriate depends on several factors, including what has been seen on ultrasound, what other genetic testing has already been performed, family history, what a family hopes to learn, how they feel about potential results, and what results could mean for the pregnancy.
There is no single right choice for every family, and understanding the available options before testing and the results afterward is just as important as the test itself. Genetic counselors can help families understand testing considerations, make informed decisions, and understand what results may mean. If you are offered prenatal genomic sequencing, consider asking to speak with a genetic counselor.
To request a virtual appointment with a Certified Genetic Counselor at Genetic Support Foundation, visit our website or call us at (844) 743-6384.