Genetic testing and early ultrasounds
By Kidspot Team |
Genetic testing and early ultrasounds
Genetic tests during pregnancy are used to screen for or detect specific inherited disorders in unborn babies. Medical and technological advances have now made it possible for early ultrasounds and blood tests to estimate the chance (or possible 'risk') of an unborn baby having a chromosomal (or genetic) abnormality. More involved tests such as 'chorionic villus sampling' (or CVS) and amniocentesis are able to diagnose a genetic disorder by examining a sample of cells obtained from inside the woman's uterus to 'map' the baby's chromosomes (or genes).

Ultrasounds done at around 18 weeks of pregnancy were the first form of testing used to screen for health disorders. While, they can usually detect obvious physical abnormalities (such as kidney and heart defects) they are not able to reveal the actual genetic 'make-up' of a baby (you can read more in ultrasounds).

In recent years it has become an increasingly accepted part of routine pregnancy care in women aged 35 and over. However, even younger, very low risk women request genetic testing for various personal reasons.

Many parents do not realise that genetic testing is OPTIONAL, no matter what the woman's age is. In fact, up to 40% of women over 37 choose not to have genetic testing. Genetic tests have far reaching implications.

Your caregiver may offer you genetic testing (or you may request it) at your first pregnancy visit, but if your first visit is not scheduled until you are 11 to 12 weeks pregnant or later, you should try and organise some genetic counselling before this time.

Genetic counselling involves providing information relating to the risks and possibilities of giving birth to a child with a genetic disorder and discussing the options available, including a full explanation of all genetic tests. You may choose to see a genetic counsellor and perhaps consider having testing if you:

  • Are aware (or suspect) that you or your partner suffer from or carry a genetic disorder.
  • Have had a previous baby with a genetic disorder or know other members of the family who have had babies born with a specific inherited abnormality, such as Down's syndrome or (or a neural tube defect or 'NTD').
  • Have experienced recurrent miscarriages or a previous baby has died during the pregnancy or soon after birth.
  • Come from an ethnic background that has a higher than average incidence of a specific health condition or genetic disorder. For example, a condition called Tay-Sachs disease is more common in Jewish and French Canadian populations, thalassaemia in Mediterranean populations and sickle cell in African populations.
  • Have a partner who is a close family relative. This is referred to as a 'consanguineous relationship'. In some parts of the world consanguineous marriages are very common, being up to 35% in some regions. A consanguineous relationship may increase the likelihood of having a baby with an inherited abnormality.
  • Are over 35 to 37 by the time your baby is due, or the father of the baby is over 55 years. Caregivers and hospitals can vary as to when they will routinely offer genetic testing because of a parent's age.
  • Feel strongly about seeking the advice of a genetic counsellor or having genetic testing.


Seeing a genetic counsellor does not necessarily mean you have to accept genetic testing. Many parents have counselling just to obtain information and then decide not to test. Ideally, you should feel supported in the decisions you make whether you accept or decline tests or decide to continue or terminate the pregnancy. These are all very personal choices that people need to weigh up for themselves.

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