Chromosomes contain the genetic material (DNA) and are usually arranged in pairs. The total number of chromosomes is 46. The ‘sex’ chromosomes (X and Y)
determine whether you are male (46XY) or female (46XX).
The syndromes mentioned occur when an unborn baby develops with three copies of a particular chromosome instead of the two. Depending on the syndrome, the
unborn baby may develop with significant abnormalities or malformations.
Some of the syndromes are fatal and the baby will die either before birth or shortly afterwards.
NIPT can also screen for certain abnormalities linked to the sex chromosomes. For example, Turner Syndrome occurs when there is a missing X chromosome in a girl.
NIPT is non-invasive. It ONLY involves taking a blood sample from the mother.

What are the limitations of the test?

NIPT is the most accurate screening test currently available. However, the only way to know for sure whether the fetus has a chromosomal problem or not,
is to have a diagnostic test such as CVS or an amniocentesis. These tests are invasive and carry a small risk of miscarriage (approximately 1.0% for CVS and
0.2% for amniocentesis).
If the NIPT test yields a low risk result, it is still highly recommended that an anatomy scan be performed at 20-22 weeks gestation to check for structural
abnormalities. NIPT does not provide information on other rare chromosomal abnormalities or physical defects such as cardiac abnormalities or spina bifida.
There needs to be enough fetal DNA in the maternal blood sample to be able to provide a result. If there is insufficient fetal DNA in the sample, another maternal
blood sample may be required. This happens in 3-4% of cases. There will be no extra charge for the second test. However, the result will be delayed.