Genetic tests in pregnancy

Prenatal screening and prenatal diagnosis

A guide for the non-expert

In recent years there have been rapid developments in prenatal genetic testing. You may have heard that we are entering the ‘genomic’ era, as we can now combine knowledge about the whole human genome with advanced laboratory and computer technologies to provide testing that looks for ever more subtle genetic changes that might have an effect on a baby’s development in the womb.

Each pregnancy is unique and every expectant parent should make decisions about prenatal testing that are appropriate to their individual circumstances. For some people, genetic testing in pregnancy can be valuable as it can provide information on the development of their baby and help in decisions about how the pregnancy and birth are managed or sometimes inform the decision to end a pregnancy. However, it is important to know that genetic testing has limitations. No test can guarantee a healthy baby. While tests might diagnose a genetic condition or a significant genetic change, it is not always possible to predict what exactly this might mean for a child after birth. Sometimes genetic tests will not find a reason for a baby not developing as expected or there may be uncertain findings that don’t fully explain the baby’s symptoms.

This information is designed to help you better understand some of the language you will hear around genetic testing, what can be done in pregnancy and what genetic tests might be available to you. It does not replace discussions with expert health care professionals, but we hope you will go into these discussions better informed and able to ask the questions that are important to you so that you can decide if you want a particular test.

We have provided a glossary that includes some of the more common terms you may hear in relation to genetic testing.

These illustrations show you what are genetic tests are looking at:

From chromosome to single base