What is a congenital disorder?

A congenital disorder is a condition that is present from birth. Congenital disorders can be inherited or caused by environmental factors. Their impact on a child’s health and development isn’t always severe, and sometimes it can be quite mild. However, a child with a congenital disorder may experience a disability or health problems throughout life.

It’s natural to be concerned about congenital disorders if you’re pregnant or planning a pregnancy, especially if your family has a history of a particular disorder. It’s possible to test for some, but not all disorders during pregnancy, and there are also things you can do to reduce the chances of your baby being born with a congenital disorder.

What are the most common congenital disorders?

Some common congenital disorders are:

• cleft lip and cleft palate — usually diagnosed during routine scans in pregnancy
• congenital heart disease ­— including a hole in the heart, a valve problem or a problem with the blood vessels. These are usually diagnosed during routine scans in pregnancy or during newborn screening.
• cerebral palsy — usually diagnosed in the first few years of life
• Fragile X syndrome — may be diagnosed through genetic testing during pregnancy or in the first few years of life
• Down syndrome (Trisomy 21) — usually diagnosed through genetic during pregnancy
• spina bifida — usually diagnosed during routine scans in pregnancy
• cystic fibrosis — usually diagnosed during newborn screening

What tests for congenital disorders are available in pregnancy?

Testing for some congenital disorders, such as Down syndrome, can be performed using a blood test from 10 weeks of pregnancy onwards. Although many parents choose to have tests during pregnancy, it is not compulsory. Some parents choose not to have tests.

Screening tests are designed to identify babies who may be at increased risk of a congenital disorder. If a screening test does not rule out your baby having a congenital disorder, the next step is to have a diagnostic test.

Diagnostic tests, such as ultrasound scans, blood tests and sometimes urine tests, aim to identify babies who have a congenital disorder and to find out what that disorder is.

However, it is not possible to test for all congenital disorders during pregnancy, and testing is not perfect.

Chorionic villus sampling (CVS)

Chorionic villus sampling, or CVS, is usually performed between 10 and 13 weeks of pregnancy if screening tests show your baby may have a congenital disorder. CVS can be used to diagnose babies with Down syndrome or other genetic conditions. You would be given a local anaesthetic and a doctor would use a needle to collect a small sample of cells from your placenta, which is then sent for testing.

Amniocentesis

This test is done after 15 weeks of pregnancy and may be done instead of, or as well as CVS. It can provide a definite answer as to whether your baby has Down syndrome or another congenital disorder.

Amniocentesis involves taking a small amount of fluid from around your baby, using a needle and after a local anaesthetic, which is then sent for testing.

There is a very small risk of miscarriage with both CVS and amniocentesis.

Can congenital disorders be prevented?

If you have a personal or family history of certain congenital disorders, you can have genetic tests before you become pregnant. You may wish to meet with a genetic counsellor to discuss your family history, the likelihood your baby will have any congenital disorders, and possibly to arrange to have genetic testing.

If you are having in vitro fertilisation (IVF) treatment, your embryo can be tested at 2 to 4 days old, before it is implanted into your uterus.

Other things you can do to try to prevent congenital disorders include:

• eating a healthy diet with enough vitamins and minerals, in particular folic acid, during the reproductive years
• taking folic acid supplements before you become pregnant and for the first trimester of pregnancy
• avoiding alcohol, smoking and other drugs because these can harm the fetus
• controlling diabetes and gestational diabetes
• avoiding exposure to chemicals in your environment, such as pesticides or lead
• being vaccinated, especially against rubella

Newborn testing and assessment

A paediatrician and other health professionals examine your baby in the first few days of life to check for hearing problems, heart conditions, and blood, metabolism and hormone disorders. This is called newborn screening. Early detection of such problems can often prevent them from becoming more serious physical, intellectual, visual or hearing disabilities.