Prospective parents can be tested to see if they carry genes that could cause a health problem for their children. The status of the carrier is checked, using a blood test, before conception. If there is a problem, you can look for other options, such as IVF.
What is a carrier status check?
Most people can carry genetic mutations that are likely to cause a health problem, even though they do not have this problem. In some cases, if they conceive with a partner who carries the same type of gene, each conceiving child will have a 1 in 4 chance of being born with this condition.
Testing your genes before trying to conceive is called a carrier status check. It allows you to consider different options, such as having IVF or making sure you have a diagnostic test during pregnancy.
Various screening options are available, including:
- The 3-gene carrier screen, which screens for carriers of cystic fibrosis, spinal muscular atrophy and fragile X syndrome
- Single gene carrier screening, which checks for a specific genetic condition
- Extended carrier screening, which screens for carriers of many common and rare genetic conditions
Who Should Have a Carrier Status Check?
Australian guidelines recommend that all women or couples planning a family be given information about carrier status screening so they can understand their risks. It doesn’t mean you need the test – but you can discuss it with your doctor.
Before you try to get pregnant, consider talking to your doctor about your family history and whether you’re at risk for 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 counselor. Even if they don’t think you’re at risk, you can still get the scan done.
You can also check the carrier’s status during the first 12 weeks of pregnancy.
Is a carrier status check right for me?
A carrier status check may prevent you from having a child with a serious health condition that could cause disability or death. Although it is very rare for you and your partner to carry the genes that cause these problems, there are hundreds of diseases that are caused by genetic problems.
However, a carrier status check doesn’t capture every health condition, and it won’t guarantee you’ll have a perfectly healthy baby. It does not replace pregnancy tests such as the non-invasive prenatal test (NIPT) or the combined first-trimester screening (CFTS), which you had in the first 12 weeks of pregnancy.
It’s a good idea to talk to your doctor about the pros and cons of carrier status screening. Only you and your partner can decide if you want to move forward.
How do I arrange a carrier status check?
Carrier screening is usually ordered by a doctor, obstetrician, fertility specialist, midwife, or genetic counselor. They will fill out a test order form that you take to your local disease collection center for a blood test. The genetic test will be done in a specialized laboratory.
Be sure to tell the person requesting the test if you have a family history of a genetic condition, so they can order the most appropriate test.
In Australia, a carrier status check can cost several hundred dollars per person. You cannot claim a refund on Medicare. Some private health funds will pay a portion of the cost if you have a family history of certain genetic diseases.
What happens after the examination?
You’ll usually get your test results back in 2 to 4 weeks. If you and your partner are carriers of a defective gene, this does not mean that your child will definitely be affected.
You can talk to your doctor or genetic counselor about the best course of action. This may include more tests, artificial insemination if you are not already pregnant, or tests in early pregnancy such as a prenatal blood test (NIPT) for chronic villus sampling (CVS) or amniocentesis.
If your carrier status screening test is positive, it is still up to you whether to go ahead and carry a child or avoid having children. A genetic counselor can give you the information you need to make a decision.