Tips for Your Amniocentesis

Why Have an Amniocentesis?

Having an amniocentesis can be a very nerve-wracking experience, and you may be especially anxious before the procedure begins. The primary reason a woman's doctor will recommend an amniocentesis is if he feels she is at risk for having a baby with a chromosomal abnormality such as Down syndrome. Women who are thirty-five and older will often have an amniocentesis because they are at a higher risk of delivering a baby with an abnormality. Women who have had an abnormal ultrasound or have a family history of birth defects will also likely undergo an amniocentesis. If a woman has previously had a baby with a birth defect, both she and her doctor may see the need for an amniocentesis test.

While the test will not detect all birth defects, it will generally be able to tell whether the baby has cystic fibrosis, muscular dystrophy, Tay-Sachs, sickle cell, certain neural tube defects such as spina bifida and anencephaly and, of course, Down syndrome. An ultrasound is used during the amniocentesis, and certain birth defects such as cleft palate, club foot and heart defects may show up on the ultrasound. An amniocentesis is also the best way to find out the sex of your baby before his or her birth, if you would like to know. Occasionally an amniocentesis is done during the third trimester in order to determine whether the baby's lungs have matured to a level where delivery will be safe. The amniocentesis test results are considered to be 98%-99.2% accurate, although they cannot determine the degree of severity of the specific abnormality.

How is An Amniocentesis Performed?

An amniocentesis is generally performed between the 14^th and 20^th week of pregnancy, although in certain cases it may be performed either a bit earlier, or later. The doctor will insert a long, thin needle through the abdomen and into the uterus and amniotic sac, guided by the ultrasound. A sample of the fluid in the amniotic sac is extracted, and this is what is tested. The amount of amniotic fluid which is withdrawn is less than one ounce. Just as with most things in life, often our expectations of an event are much worse than the actual event-although sometimes the reverse is true.

Occasionally the doctor will have to attempt the procedure more than once due to an extremely active baby who is moving around and making it hard for the doctor to find the amniotic sac. Also, some women have noted that their doctor misjudged the length of needle necessary, and had to get a longer needle and try again. Although these are unfortunate, they are the exception rather than the rule. Though you are rightfully nervous about the procedure and about the risks involved, do your best to relax and think of something besides the needle being poked into your stomach. Having your partner or a close friend with you for support is invaluable.

What are the Risks and After-effects of Amniocentesis?

Many women experience some cramping following the amniocentesis, while others will experience a small amount of fluid leakage or irritation at the puncture site. As long as they don't last more than a few hours, you and your baby are probably just fine. You should rest as much as possible for the remainder of the day following your amniocentesis; this includes no heavy lifting, no traveling, no cooking, cleaning, or laundry, and no sexual intercourse. Severe cramping or bleeding, or a fever are not normal effects of the amniocentesis; if you experience any of these call your physician immediately.

The Risk of Miscarriage

The biggest risk of having an amniocentesis is the possibility of miscarriage. Statistically, approximately one in 400 women who undergo an amniocentesis in a medical facility where it is routinely performed will have a miscarriage, while those who have the procedure done in a clinic where it is less commonly performed may have as much as a one in 200 chance of having a miscarriage. A miscarriage can be caused by the amniotic fluid becoming infected, when the needle accidentally pokes the fetus, or when the needle causes excessive bleeding during the test. Because the risk of miscarriage is relatively high, parents need to weigh the risk against the possible benefits prior to agreeing to have an amniocentesis performed.