Most paternity tests are carried out any time after the birth of a child up until adulthood or even post-mortem. Sometimes, paternity tests are carried out during pregnancy. In this case, they are referred to as prenatal paternity tests. Prenatal paternity tests are not quite as quick and simple to carry out, mainly because of the method of sample collection required for such a test.
If a paternity test is carried out following the birth of a child, sample collection is simple. Oral swabs in such an instance are the quickest way of collecting samples. All you need to do is rub the swabs inside the mouth of the child for a couple of seconds so as to collect a sample of check cell from which the DNA will be extracted. However, if the baby is still in the womb collecting a DNA sample will not be so simple.
So how the baby’s DNA collected from a pregnant woman?
There are two prenatal fetal DNA sampling methods which can be used in order to have a sample of the unborn child’s DNA. The one that can be carried out earliest in the pregnancy (possible at between 10-12 weeks of gestation) is known as chorionic villus sampling. Using a catheter inserted through the vagina or a needle through the pregnant belly, a qualified OBYN can extract a sample of the baby’s tissue (the sample is known as chorionic villus). The procedure requires applying local anesthetic. Following the procedure, the mother may experience minor discomfort or soreness.
At around 15 weeks of gestation, amniocentesis can be performed. The procedure takes around 45 minutes and involves inserting a needle into the womb. Once inside, a sample of amniotic fluid can be extracted and sent for laboratory analysis. The OBGYN must of course make sure he or she inserts the needle into the correct place and moreover, must also make sure that the needle does not injure the baby. To be able to gauge where to insert the needle and its location once inside the womb, an ultrasound will be required. An ultrasound is also used when carrying out chorionic villus sampling
Amniotic fluid contains high volumes of the unborn baby’s DNA and using this DNA, scientists can extract the baby’s DNA profile. Following amniocentesis, the mother might experience chills or run a fever. But further to this, other problems could arise. Although rare, both amniocentesis and chorionic villus sampling can result in a miscarriage. The reason could be either a human error in which the needle injures the baby by coming into contact with it or because of an infection in the womb.
A recent scientific achievement
Over the past two decades scientists have found and refined another method of collecting the unborn baby’s DNA that does not require anything close to amniocentesis or chorionic villus sampling. They have successfully managed to take samples of fetal cells from the mother’s blood. This test is indeed extremely accurate and is just as importantly, risk free. A simple, quick standard medical blood draw is enough to have the baby’s DNA profile. Once the laboratory have this in hand, they can compare it to the DNA profile of the alleged father to see if there is match (thus, confirming he is the biological father) or perhaps not a match (obviously confirming that he is not the biological father. One further advantage to this test is that it can be carried out before amniocentesis and chorionic villus sampling. Prenatal paternity testing using just the mother’s blood is possible starting at nine weeks of gestation.
Joan Hayes is a family therapist and social worker. She also enjoys writing and works as a free lance writer in her spare time. Joan enjoys writing about a variety of topics related to her job but also on other topics such pregnancy and genetic research. The author writes articles for the article base on: easyDNA New Zealand .