The Science behind the Prenatal Paternity Test

Invasive DNA sampling techniques

The risk aspect of these medical procedures lies in the fact that for both amniocentesis and chorionic villus sampling (CVS), a needle needs to be inserted transabdominally into the womb. This procedure requires the application of a local form of anaesthetic and an ultrasound. The stress caused by the presence of the needle in the womb, the actual puncture of the amniotic sack and the contact of the needle with the fetus could all lead to serious consequences such as deforming or injuring the baby’s limbs or a spontaneous abortion (miscarriage).

EasyDNA’s prenatal paternity test distinguishes itself from all other tests in pregnancy for the following reasons:

• The test is non-invasive (there is no risk involved for both the foetus and the mother!)
• It is quick and straightforward in terms of sampling
• It can be done starting at 7 weeks from conception (meaning that you will be in your 9th week of pregnancy starting from the first day of your last menstrual period)

Prenatal testing using cell-free fetal nucleic acids in maternal blood

Well over a decade ago, a study pioneered a method of analyzing fetal DNA in pregnancy that is 100% risk-free, eliminating all risks of harming the baby or of miscarriage. This study enabled the development of the risk-free prenatal paternity test we offer today. The test we offer only requires a medical blood draw from the expectant mother and mouth swab samples from the alleged father.  From this blood sample, we can isolate the unborn baby’s cell-free DNA, compare it to the DNA of the alleged father and determine whether the tested male is the biological father or not.

Fetal genetic material in maternal blood

One of the principal methods by which foetal cells find their way into the maternal blood supply is by apoptosis of placental cells; placental cells die, detach from the placental wall and get replaced with new cells. Then, the dead cells get picked up with the circulatory blood supply and get flushed out of the body. Cells are continuously dying and being replaced meaning that this process continues throughout pregnancy. In fact, the volume of dead placental cells in a maternal blood sample will increase as pregnancy progresses (due to the increase in size of the fetus).

The method of analysis

This test differs from the other methods of DNA analysis we offer (for example, standard after birth paternity testing, sibling DNA testing and DNA profiling). In order to analyse the cell-free fetal DNA in the maternal blood sample, the laboratory uses what is known as microarray single nucleotide polymorphism technology. The term single nucleotide polymorphisms or SNPs refers to variations in the genetic code (more accurately and scientifically put, in the sequence of nucleotides) from one individual to the next. The analysis of single nucleotide polymorphisms enables a very accurate discrimination of fetal DNA. The prenatal paternity test analyses 2,688 SNPs.

The accuracy of the test

Our non-invasive prenatal test offers you a certitude of 99.9% in cases where the tested father is the biological father of the foetus. If the tested male is not the biological father, he will be excluded with a 100% probability. However, it is extremely important that the nine-week time frame has passed before collecting your samples as this would normally mean that the volume of fetal DNA is high enough to conclude the test.

Learn more about how this DNA test can help you to determine your baby’s paternity!