Prenatal DNA Test
Paternity can be determined in the early stages of pregnancy thanks to prenatal testing. Prenatal paternity testing requires the collection of fetal DNA samples to be able to compare the child's genetic profile to that of the alleged father. There are three methods available to collect DNA samples from a pregnant woman.
Amniocentesis and Chorionic Villus Sampling
These two methods are the ones that have been around for longest. Whether amniocentesis is carried out or chorionic villus sampling depends on how many weeks pregnant you are. Chorionic villus sampling is carried out at about ten weeks while amniocentesis can be done at about 13 weeks. Both tests are carried out by a qualified OBGYN, and both entail specific risks and have particular side effects.
Amniocentesis involves the application of local anesthetic to the belly and insertion of a needle into the womb. Amniotic fluid is rich in fetal DNA but degrades quite quickly which means it needs to be tested almost immediately.
Chorionic villus sampling is a procedure which extracts a small tissue sample from inside the womb. The tissue sample can be obtained by inserting a catheter into the uterus through the cervix.
Both tests carry the risk of miscarriage or in rare cases injury and deformity of the baby's limbs through contact with the needle inserted.
Noninvasive prenatal testing for paternity is the latest scientific innovation. Instead of collecting fetal DNA samples from inside the womb, scientists can successfully extract the baby's DNA from the maternal blood sample. This is a zero risk test.
The sample may be obtained from the amniotic fluid surrounding the mother's womb. This process is called Amniocentesis. Another method for obtaining the sample is Chronic Villus Sampling (CVS). In this case, the sample is derived from the placental surface.
In both cases, the procedure will be performed with the use of ultrasound to ensure the safety of the mother as well as the unborn child. The system may be done in two ways. The objective of both procedures is to obtain a small tissue sample from outside of the sac.
There are risks involved in prenatal DNA testing. The chance would be the same as a miscarriage, which is about 1:200. There have been cases reported wherein congenital disabilities in the child's toes or fingers were noted after an Amniocentesis or CVS was performed. Most of these cases were recorded when the procedures were completed before the 9th week of pregnancy. CVS is usually recommended between the 10th and 12th week of pregnancy and Amniocentesis between the 12th and 21st week.
It is always best to consult an Obstetrician or a Gynecologist to discuss the implications of each procedure before deciding to proceed.
If the results of the test are to be legally valid, the test needs to be performed using a Chain of Custody procedure. There are quite a few added documentation in a Chain of Custody procedure, and the costs will be higher than an In-home method where the results are not legally valid.
If the parents are not comfortable with the prenatal DNA testing procedures and the risks associated, then the alternative is to perform a normal paternity test at the time of birth. Only a small amount of DNA is required and this can be safely obtained from a newborn by using a buccal swab.