Amniocentesis and Chorionic Villus Sampling
Preparation
On the day of your appointment, you need to bring your referral and your blood group card, if you have one. There is no preparation for the ultrasound or the procedure. The ultrasound is done transabdominally. This means that we put gel on your abdomen and look at your baby through the abdominal wall wall. You don't need a full bladder, although a little urine in the bladder may be useful in some circumstances.
Photographs and videos
DVD recording and VHS video taping facilities are available. The ultrasound examination will be recorded free of charge. It is not necessary to bring a DVD disk or video cassette as they are provided by us at no extra charge. You will also receive a picture of your baby. The procedure is usually not taped.
Children
We welcome children at our practise but when you are coming in for a procedure we do encourage you to find a babysitter and attend only with your partner or a friend. You will feel nervous about the procedure and small children pick up on that. They may become restless and increase the stress for you. Your partner may need to take the children out for a walk during the procedure instead of being able to support you.
The procedure
You can find more information about amniocentesis and CVS under 'our services'.
Although most women find the procedure emotionally very stressful, the physical part is in general not very painful. The pain of an amniocentesis is comparable to that of a blood test. The pain of a CVS is mainly that of the local anaesthetic, which may sting when it is injected. This is probably comparable to a local anaesthetic at the dentist.
We usually recommend that a companion drives you home but most women are quite capable of driving themselves home if need be. You should organise to have some help at home so you can rest until the next day. There is however no need to go to bed.
You can experience some cramping of the uterus in the hours following the procedure. You can take panadol if this cramping is too uncomfortable.
If the cramping is more severe or if bleeding or fluid loss occurs, you need to contact the doctor who performed the procedure. Dr. Edwards, Dr. Piessens or Dr. Teoh will give you a card with their contact details after the procedure. Don't hesitate to contact them if you are worried. They will organise an ultrasound to check the pregnancy as soon as possible.
Why your blood group is important
The majority of people have a Rhesus positive blood group and for women with a positive blood group undergoing prenatal testing, no special precautions are necessary. If you have a Rhesus negative blood group however, you will need an injection of anti-D after the procedure. This is given like a normal injection in your muscle. The reason why you need this injection is to stop you from making antibodies against Rhesus positive cells. Because most people are Rhesus positive, there is a good chance that your partner and therefore also your baby might be Rhesus positive. When we do a procedure, there is a risk that a few positive red blood cells of your baby may get into your circulation. Your body will recognise those positive cells as foreign and instruct your immune system to make antibodies to destroy them. Once your immune system has made these antibodies, they will be present for the rest of your life and can be a threat to this or subsequent pregnancies. They can cross the placenta and destroy the baby's positive red blood cells, causing anaemia and even death. When we give you an anti-D injection we basically give you anti-positive blood cell antibodies. These antibodies will clear up any positive red blood cells in your circulation before your immune system can be activated. Rhesus negative women need anti-D every single time there is a possibility that positive red blood cells go into their circulation: miscarriage, prenatal testing, bleeding in pregnancy, delivery of a Rhesus positive baby…
Anti-D is a blood product. It is made from blood of people who made antibodies at some stage in their lives. It is collected and processed in Australia by the red cross and is tested extensively for the different known infections. The advantages of having the anti-D far outweigh the possible small risk of having a blood product.
The results
You can find more information about the 5-probe FISH and the banded karyotype in 'Amniocentesis and CVS' under 'our services'.
The result of the 5-probe FISH is usually available the next working day.
The result of the banded karyotype usually takes 2 weeks.
We arrange with you when and where to contact you with the results. We will contact your obstetrician immediately in case of an abnormal result.
