What is Non-Invasive Prenatal Paternity Testing

Prenatal paternity testing involves determining paternity of a child before it is born. A non-invasive technique is one that does not present the risk of entering the womb for a DNA sample by using a blood sample from the mother and one from the alleged father.

The types of prenatal paternity testing currently carried out, such as the invasive amniocentesis and chorionic villus sampling (CVS) present a definite risk to the baby and even miscarriage. In amniocentesis, a needle is inserted into the mother’s abdomen and then through the amniotic sac to extract a sample of amniotic fluid. This offers up to 0.5% (1 in 200) chance of a miscarriage.

In CVS, either a catheter is inserted through the vagina and cervix, or a needle inserted through the abdomen, to take a sample of part of the placenta in the early stages of fetal development. This offers up to 1% chance of a miscarriage. Each of these paternity testing techniques provides fetal DNA that can be used to determine paternity.

These tests are dangerous to the developing child, and even a 0.5% risk of miscarriage would seem too high a risk to take simply to determine paternity during the early stages of pregnancy. More advanced laboratories use a technique whereby fetal DNA found in the mother’s blood can be used rather than samples taken direct from the amniotic sac or the placenta.

100% Safe Test

This takes less time and is less costly than expensive surgical procedures, but most importantly of all, the test offers no risk whatsoever to the baby. It is 100% safe and is easy to carry out. There also no risk of the diagnosis being wrong because the procedure uses cell-free DNA in the blood of the mother – that is DNA that is not contained within cells but that constantly enters the blood stream of the mother from the placenta throughout pregnancy.

DNA contained within body cells is able to remain in the mother’s blood for many years after a previous pregnancy and hence corrupt the results. This is the type of DNA used by other non-invasive blood tests and is subject to error. Using cell-free DNA the test is completely accurate, the DNA being related solely to the current pregnancy by definition.