i . Fetal Karyotype
A karyotype test looks at the size, shape, and number of your chromosomes. Chromosomes are the parts of your cells that contain your genes. Genes are parts of DNA passed down from your mother and father. They carry information that determines your unique traits, such as height and eye color.
People normally have 46 chromosomes, divided into 23 pairs, in each cell. One of each pair of chromosomes comes from your mother, and the other pair comes from your father.
This test requires fetal cells obtained through Amniocentesis/ Chorionic Villus Sampling
ii. Microarray
This approach can accurately detect the number and structural abnormalities of chromosomal imbalances and detect chromosomal alterations such as microdeletions and microduplications.
This test requires fetal cells obtained through Amniocentesis/ Chorionic Villus Sampling
iii . Non- Invasive Prenatal screening (NIPT)
This test analyzes cell free DNA in maternal blood and gives a strong indication of whether the baby is at high or low chance of having trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome) or trisomy 13 (Patau syndrome).
The test identifies 99%, but not all, of the babies with trisomy 21, 98% of babies with trisomy 18 and 90% of babies with trisomy 13.