The tests
Understanding 'the numbers'
Things to consider
Emotional reactions
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).
More advanced forms of genetic testing were first introduced in the 1970's. However, over the last 5 to 10 years genetic tests have become an increasingly accepted part of routine pregnancy care, especially for women in their late 30's and early 40's. When genetic tests were first introduced for the reason of 'advanced maternal age', they were generally only offered to women 40 years or older (the woman's age being taken at the baby's due date, not at conception). Later on, the recommendations were lowered to women 37 years or older and in recent years it has come down to 35 years. 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. This means it is very important to consider the many issues associated with them before accepting them.