How Does NIPT Work?

NIPT is a simple blood test that can help to detect chromosomal abnormalities and other genetic conditions. If you’re thinking about having one of the NIPT tests that we provide at The Birth Company, then you may be wondering how it all works. How can we check your baby’s genes using just a sample of your blood?

nipt test

How Fetal DNA Can Be Analysed

The placenta forms a barrier between mother and baby that allows some things to pass through while blocking others. For example, the circulatory systems are kept separate so that the baby’s blood never passes into the mother. However, some cells and fragments of cells can break away from the placenta and pass into the mother’s bloodstream. Since the placenta was produced from the same fertilised egg as the baby, the cells are genetically identical to those of the unborn baby. It is the DNA from the placenta that will be captured and analysed during NIPT.

  • Enough fetal DNA is present in the mother’s bloodstream by the 10th week of pregnancy to be collected and used for NIPT.
  • Most of us have 23 pairs of chromosomes in each cell, but sometimes an extra chromosome is inherited, which can cause problems.
  • Each chromosome contains specific genes, so it is possible to tell which chromosome each fragment of DNA came from.
  • If there are more fragments from a chromosome than expected, this indicates that there is a high probability the baby is carrying an extra copy of this chromosome.

Having NIPT Tests

If you decide to have NIPT, you will simply need to provide a sample of your blood to be tested in the lab. The process will be very similar to having any other kind of blood test. Once the sample has been taken, the fetal DNA will be extracted from it and analysed. The tests can check the number of chromosomes in the fetal cells or check for specific genetic faults if you are at risk. You will be able to discuss the results in detail with your doctor after the test to ensure that you understand what they mean and what your options are if any abnormalities are detected.

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Clinic Locations

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137 Harley Street, London W1G 6BF
Nearest Underground Tube Stations

Baker Street
Regent’s Park
Great Portland Street


Talbot Road, Talbot Road, Alderley Edge, Cheshire SK9 7HR
Nearest Overground Train Station

Alderley Edge