Alternatives: invasive prenatal diagnosis

The non-invasive prenatal exam that analyzes fetal DNA present in maternal blood is just one of the options for the pregnant woman to determine the risk of chromosomal pathologies during pregnancy.

There are several screening that can be performed.
In particular, a more accurate cytogenetic analysis can be obtained through the “invasive prenatal diagnosis”, which can be performed on chorionic villi or amniotic fluid.

Chorionic villi collection (placental tissue that, although separated from the fetus, it contains the same DNA), or chorionic villus sampling, is performed between the 11th and the 12th week of gestation and consists in the collection, under ultrasound control, of a little sample of chorionic villi through an injection across the maternal abdomen. This collection implicates an abortion risk lower than 2%.
The cytogenetic testing is conducted on the DNA extracted by the fetal cells contained in chorionic villi.

The collection of the amniotic fluid, or amniocentesis, is performed through an ultrasound-guided transabdominal injection between the 16th and the 18th week of pregnancy and implicates a risk of miscarriage lower than 1%.
In this case, the cytogenetic testing is conducted on the fetal cells present in the amniotic fluid.

The aforementioned investigations can, furthermore, provide a complete chromosomal analysis of the fetus and are particularly recommended to pregnant women over the age of 35.