What is it?

• Amniocentesis is the procedure by which amniotic fluid, which surrounds the fetus (unborn baby), is obtained for studies.
• This involves using a local anesthetic to numb the skin, then inserting a needle through the abdomen and into the uterus. Ultrasound is used to guide the placement of the needle.
• For prenatal diagnosis, the procedure is typically performed at 15-18 weeks from the last menstrual period.

What can I learn from the amniocentesis?

• The tests which are run on the amniotic fluid depend on why the test is being done.
• A common test is chromosome analysis which will detect disorders such as Down syndrome.
• Biochemical analysis of the fluid can detect certain other birth defects such as spina bifida.
• In some cases, DNA is analyzed to diagnose genetic disorders.

What are the risks and benefits?

• The risks include the possibility of miscarriage, which is well below 1% when an experienced physician performs the procedure.
• Another risk is for leakage of amniotic fluid following the procedure.
• Slight cramping may occur during or after the amniocentesis.
• Rarely, fluid cannot be obtained.
• Also, the tests run on the fluid may be unsuccessful.
• These risks should be fully discussed with your health care provider when deciding whether the procedure is right for you.
• The benefits include knowing more about the health status of the fetus.
• For most women, this means finding out that the fetus is free of the disorder being tested.
• Many women will gain peace of mind knowing that no problems have been identified.
• If fetal abnormalities are found, the couple will be able to learn more about the condition and make decisions regarding the pregnancy.

• It is important to know that there is no test available which can identify all birth defects or all types of mental retardation.

What is it?

• CVS is another method of prenatal diagnosis.
• This procedure involves sampling cells from the placenta for genetic studies.
• The procedure is performed at 10-13 weeks from the last menstrual period.
• The cells are obtained either by a vaginal or transabdominal method.
• Generally, fewer physicians are experienced with CVS than with amniocentesis.

What can it tell us?

• Cells obtained by CVS can be used for chromosome analysis or DNA studies.
• CVS is not useful for detecting spina bifida or related disorders.
• A follow-up ultrasound exam and a blood test to screen for spina bifida are routinely done in the second trimester, usually at 16-18 weeks.

What are the risks and benefits of CVS?

• Most experts feel that the risk of pregnancy loss may be higher with CVS than with amniocentesis.
• The risk is approximately 1% with CVS.
• There is controversy regarding a possible increased risk of specific birth defects.
• Having the procedure performed at 10 to 13 weeks by a physician experienced with the procedure can minimize these risks.

• The main benefit with CVS is that the results are available earlier than with amniocentesis.
• Many women feel that this affords them greater privacy and safer options if an abnormality is detected.

What is it?

• An ultrasound evaluation, or sonogram, involves the use of sound to generate an image.
• Some of the terminology used can be confusing.
• Sometimes a targeted ultrasound is called a level 2 or level 3 ultrasound.
• A targeted ultrasound evaluates fetal size and anatomy, the appearance of the placenta and the amniotic fluid volume.
• Some, but not all birth defects can be detected.
• The age of the fetus is important in determining how well the anatomy can be visualized.
• Other factors involve the type of equipment used, the experience of the ultrasonographer, and the body type of the woman.

What are the risks and benefits?

• There does not appear to be any risks associated with ultrasound.
• However, there can be situations where the importances of the ultrasound findings is unclear.

• The main benefit is that it is a non-invasive method of obtaining information about the well being of the fetus.
• Also, ultrasound can identify many fetal birth defects that are not associated with chromosomal or genetic syndromes.
• Finally, ultrasound measurements of fetal structures can confirm or correct your due date.

How do I decide if testing is right for me?

It is important to discuss your questions and concerns openly with your health care provider. It may be helpful to weigh the "pros and cons" of testing. Some questions you might ask yourself are:

• Would the information the testing provides be helpful to me?
• Am I willing to take some risk to get this information?
• What if I find out there is a problem?
• Do I want to have this information at a time when choices are available?

There is no right or wrong answer to these questions. Each woman must decide what she feels comfortable doing. Some will choose to have prenatal diagnosis, while others will decide against having it.
It is important to remember that by far most women who have prenatal testing receive normal results and have no complications from the procedure.

There is additional information at this website about some of the tests discussed here, so please explore further. If you need the name of a genetics professional in your area, ask your health care provider or check out some of our links.