Parents-to-be can be screened to see whether they carry genes that could cause a health problem in their baby. Screening for carrier status, using a blood test, is done before the baby is conceived. If there is a problem, you can look at other options, such as IVF.

What is carrier status screening?

Most people can carry gene mutations that, potentially, could cause a health problem, even though they do not have the problem themselves. With some conditions, if they conceive with a partner who carries the same type of gene, every child they conceive will have a 1 in 4 chance of being born with the condition.

Testing your genes before you try for a baby is called carrier status screening. It lets you consider different options, like having IVF or making sure you have diagnostic testing during pregnancy.

Different screening options are available, including:

• a 3-gene carrier screen, which screens for carriers of cystic fibrosis, spinal muscular atrophy and fragile X syndrome
• a single-gene carrier screening, which screens for one specific genetic condition
• expanded carrier screening, which screens for carriers of many common and rare inherited conditions

Who should have carrier status screening?

The Australian guidelines recommend that all women or couples planning a family should be given information about for carrier status screening so they can understand their risk. It does not mean you need the test — but you can discuss it with your doctor.

Before you try to fall pregnant, consider talking to your doctor about your family history and whether you might be at risk of carrying a genetic condition. They will be able to advise on whether screening is right for you. If your doctor thinks you are at risk, they will refer you to a genetic counsellor. Even if they do not think you are at risk, you can still have the screening done.

You can also be screened for carrier status during the first 12 weeks of pregnancy.

Is carrier status screening right for me?

Carrier status screening may prevent you from having a baby with a serious health condition that could cause disability or death. Even though it is very rare for you and your partner to both carry the genes that cause these problems, there are hundreds of diseases that are caused by genetic issues.

However, carrier status screening does not pick up every health condition, and will not guarantee you will have an entirely healthy baby. It does not replace pregnancy tests such as non-invasive prenatal testing (NIPT) or combined first trimester screening (CFTS), which you have in the first 12 weeks of the pregnancy.

It is a good idea to talk to your doctor about the pros and cons of carrier status screening. Only you and your partner can decide whether you want to go ahead.

How can I arrange carrier status screening?

Carrier screening is usually requested by a doctor, obstetrician, fertility specialist, midwife or genetic counsellor. They will fill out a test request form that you take to your local pathology collection centre for the blood test. The genetic testing will be done in a specialist laboratory.

Make sure you tell the person who is ordering the test if you have a family history of a genetic condition, so they can order the most appropriate test.

In Australia, carrier status screening can cost several hundred dollars per person. You cannot claim any of the money back on Medicare. Some private health funds will pay part of the cost if you have a family history of some genetic diseases.

What happens after the screening?

You will normally get the test results back in 2 to 4 weeks. If both you and your partner are carriers of a faulty gene, it does not mean your baby will definitely be affected.

You can talk to your doctor or a genetic counsellor about the best course of action. This might involve more tests, IVF if you are not already pregnant, or tests in early pregnancy such as the non-ivasive pre-natal blood test (NIPT) chronic villus sampling (CVS) or amniocentesis.

If the carrier status screening test is positive, it is still up to you whether you go ahead and conceive a child or avoid having children. A genetic counsellor can give you the information you need to make the decision.

If you have more questions, call Pregnancy, Birth and Baby on 1800 882 436 to talk to a maternal child health nurse.