The foetal karyotype is the set of all the chromosomes of the foetus, stained with a banding pattern and arranged in order. Studying the karyotype allows us to detect alterations in the number of chromosomes (monosomies, trisomies, and triploidies) and any structural alterations in the chromosomes (translocations, inversions, deletions, and duplications), whether they are balanced or unbalanced.
Step-by-Step
How does it work?
Foetal karyotype studies require an invasive technique to obtain foetal cells which are then cultured in the laboratory. Either desquamated foetal cells collected from amniotic fluid or cells obtained from a chorionic villus biopsy are used.
Who is it for?
When is it recommended?
A foetal karyotype study is recommended in cases where there is a suspected chromosomal abnormality as follows:
In parents who are carriers of a chromosomal alteration.
Following a result of a high risk of a chromosomal abnormality in the first trimester screening or in the maternal blood prenatal testing.
Where ultrasound abnormalities consistent with the presence of aneuploidy (for example, increased nuchal translucency) are detected.
A foetal karyotype study allows us to detect:
Alterations in the number of chromosomes (trisomies, triploidies, and monosomies).
Mosaic numerical alterations.
Structural alterations in the chromosomes (translocations, inversions, deletions, and duplications), whether they are balanced or unbalanced.