Prenatal Paternity Testing Questions
What is a CVS procedure?
Chorionic Villus Sampling is where cells from the placenta or afterbirth are removed from inside the womb using a needle. The amount of cells removed is extremely small. This is normally performed after about 11 weeks of pregnancy. Before any CVS procedure is performed you will have a discussion with the specialist performing the test.
You will be able to ask any questions you may have at this time. Your partner or someone close to you will be able to stay with you during the entire consultation and procedure if you wish. Initially, an ultrasound of the baby is performed. The afterbirth can be seen using ultrasound and the specialist will choose the best way to get the needle into the afterbirth.
Fluid is used to clean your tummy which is then covered with sterile sheets and a pain killing local anaesthetic is injected into your skin. The needle is then pushed through the numbed area and guided into the afterbirth by watching the ultrasound pictures. A smaller needle is then placed inside the first needle and used to collect some of the cells from the afterbirth.
The applicant may experience some abdominal discomfort, period-like pain or a little bleeding for the first couple of days after the procedure. This is reasonably common and in the vast majority of cases the pregnancy continues without any problems. Taking paracetamol is usually enough to give relief and is safe to take during pregnancy.
Injury to the baby during CVS is extremely rare. If carried out before 10 weeks there is a small risk of development problems with the baby’s arms or legs. This is not found in babies where the procedure has been carried out after 10 weeks which is why we will not arrange a CVS procedure before the 11th week of pregancy. Ultrasound monitoring is used continuously during the procedure and care is taken to place the needle only in the afterbirth and that it does not enter the sac where the baby is found.
IMPORTANT NOTICE: Most DNA tests are successfully performed directly from chorionic villus cells without the need for culturing. However, in some cases this may not be possible and it may be necessary to culture the cells before attempting the DNA test again. Cell culture takes approximately 2 weeks although on rare occasions cells can be very slow to culture and may require 4 weeks before the DNA test can be performed. There is no additional cost for cell culture or for re-running the DNA test using cultured cells. However, we do recommend that clients give serious consideration to waiting for an amniocentesis procedure in preference to a CVS procedure.
What is an Amniocentesis procedure?
Amniocentesis is where a needle is passed into the womb and some fluid removed from around the baby. Ultrasound is used during the procedure so the needle can be guided accurately into the fluid. This is normally performed after about 15 1/2 weeks of pregnancy.
Before any Amniocentesis procedure is performed you will have a discussion with the specialist performing the test. You will be able to ask any questions you may have at this time. Your partner or someone close to you will be able to stay with you during the entire consultation and procedure if you wish. Initially, an ultrasound of the baby is performed. The baby and womb can be seen using ultrasound and the specialist will choose where best way to place the needle.
Fluid is used to clean your tummy which is then covered with sterile sheets. Because the needle is so fine no local anaesthetic is used. The Amniocentesis needle is gently pushed through your skin into the fluid around the baby whilst watching the ultrasound pictures. A syringe is then attached to the end of the needle and about 15 mls of fluid is removed. The needle will be in place for approximately 30 seconds. After the needle is removed the baby will be looked at again on the ultrasound.
The ultrasound is often clearer if you have a full bladder which means not going to the toilet for 2 hours before the procedure. You should try to drink only 2 to 3 cups of fluid during that time. Most applicants will feel a slight pressure or even a menstrual-like cramp when Amniocentesis is carried out.
Amniocentesis should not harm your baby. The needle is kept well away from the baby and even if the baby should move up against the needle it will move away on contact. The Amniocentesis needle has a sharp internal part which is removed once the needle is in the fluid around the baby leaving only the blunt part in the womb.
What risks are involved with a Prenatal Paternity Test?
Applicants should note that both CVS and amniocentesis procedures carry a small risk to the unborn baby. Studies have indicated that the chances for foetal loss are increased by 0.5% for amniocentesis and 1% for chorionic villus sampling. We strongly recommend that you discuss these issues with your doctor.
By the 14th week of pregnancy, the chance of having a miscarriage is approximately 2%. After a CVS procedure, the risk of miscarriage is increased by 1%, to 3%, for the remainder of the pregnancy. Some miscarriages are destined to happen regardless of having the procedure and very few are caused by CVS. The more experience the specialist has, the lower the miscarriage rate will be. International Biosciences only refer applicants to carefully selected clinics and the audited pregnancy loss due to CVS is 1 in 100 procedures performed.
By the 14th week of pregnancy, the chance of having a miscarriage is approximately 2%. After an Amniocentesis procedure, the risk of miscarriage is increased by 0.5%, to 2.5%, for the remainder of the pregnancy. Therefore if you do miscarry after an Amniocentesis procedure it is more likely that you were due to miscarry than the procedure actually causing the miscarriage. The more experience the specialist has, the lower the miscarriage rate will be. International Biosciences only refer applicants to carefully selected clinics.
If your blood group is Rhesus negative you will need to receive Anti D medication after the procedure. Anti D prevents the baby's blood cells being destroyed by your immune system in future pregnancies. Please contact us for a copy of the Anti D information sheet if you are Rhesus negative.
