I am 35 years old and pregnant with my first child. My doctor suggested I have an amniocentesis but I am confused and scared. What should I do?
Amniocentesis is a procedure done during the early part of the second trimester of pregnancy (usually between 16 and 18 weeks). The pregnant woman lies down with her abdomen exposed. Ultrasound (sonogram) is used to show the doctor where the baby and placenta are located and where to safely insert the needle. The needle is inserted through the abdomen and the uterus into the amniotic fluid that surrounds the fetus. A small amount of the fluid is withdrawn -- approximately one ounce (30cc). This amniotic fluid contains cells from the fetus that can be tested. These cells have the same genetic makeup as the fetus. The patient may feel pressure but very little pain with amniocentesis, but it may cause a lot of anxiety.
Who should have one?
Any pregnant woman who:
A few scenarios may help clarify the decision-making process:
What are the benefits of amniocentesis?
The "need to know" question is answered.
The results obtained from amniocentesis are diagnostic. Although it takes two to three weeks to get the results, hearing that your baby is "chromosomally normal" is a great relief. It answers the question: Does my baby have Down syndrome or other chromosomal, genetic, or neural tube defects? It does not test for every known abnormality, including a structural abnormality such as cleft palate. Testing for specific conditions should be addressed with your midwife, doctor, or genetic counselor.
If the results do identify an abnormality, this information can be used to help you make important decisions. You'll want to
Consider where to deliver your newborn (a baby with certain known conditions should be delivered in a high-risk/tertiary care hospital that is prepared to care for your newborn's special needs; otherwise your baby might need to be transferred to another hospital while you are still postpartum!)
Consider being referred to a pediatric or surgical specialist to discuss what future issues and choices you may have to face -- even whether you want to continue your pregnancy or terminate it.
What are the risks of amniocentesis?
Basically, the greatest risk is loss of the pregnancy. The chance of this happening is statistically 1:200, meaning one woman out of every 200 who have the procedure will have leakage of amniotic fluid that cannot be stopped or develop an infection and lose the pregnancy, which could have been a normal fetus. This risk is per fetus -- each fetal sac entered with twins or triplets carries its own risk. Loss of one fetus usually causes the loss of all fetuses. If an infection develops, the pregnancy will have to be terminated since infection would risk the mother's life.
Diagnosing an abnormal baby versus losing a very much wanted pregnancy (abnormal or normal) is like comparing apples to oranges. How can a woman decide what to do, when 199 out of 200 procedures are uneventful, but her own loss would be a 100 percent disaster to her?
The good news
The vast majority of amniocentesis procedures are uneventful and the results indicate a normal fetus.
Thoughtful consideration of possible abnormal findings and the issues and choices that would have to be made place amniocentesis in a unique position. Deciding whether to have an amniocentesis is one of the most difficult decisions some women must make during pregnancy. Some women can make this choice easily, while for others it is very difficult. There is no right choice. Whatever the woman's decision is, it must be supported. She and her family have to live with the decision and outcome.