Amniocentesis is the prenatal diagnostic tool used to detect genetic or chromosomal anomalies in the fetus. The procedure is performed between the 15th to 20th week of pregnancy. In amniocentesis or Amniotic Fluid Test(AFT), a needle is inserted into the amniotic sac, through the uterus and the abdominal walls of the mother. This amniotic sac, containing the amniotic fluid is rich in fetal tissues. About 20ml of this fluid is withdrawn and the cells are cultured and studied to check for genetic abnormalities.
An alternate procedure that can be explored is Chorionic Villus Sampling (CVS). CVS is performed in earlier than amniocentesis and thus helps in early detection of any genetic anomalies, but the rate of injury to the fetus and percentage of miscarriages have found to be higher in CVS as compared to amniocentesis.
Benefits and risks
The most common disorders aimed to be diagnosed using AFT include Down Syndrome, Edwards Syndrome, Turner Syndrome, Fragile X and other inherited metabolic disorders.Infections, Rhesus factor or Rh compatibility neural tube defects such as spina bifida are also diagnosed using AFT.
Though amniocentesis is relatively safe, but there have been some risks identified to both the mother and the fetus. The primary risk to the fetus is membrane rupture, which can lead to miscarriage. The percentage of increased risk of miscarriage has been identified to be 0.08% to 2.5%.
If not miscarriage, the procedure of amniocentesis also bears risks such as bearing an affected child. This risk is directly proportional to the age of the mother, with the percentage of the risk being 0.13% at the age of 32 to 0.56% at the age of 38. (Albert R. Jonsen, Robert M. Veatch, LeRoy Walters, page 282)
The risks also increase if the procedure is performed either too soon or too late in the pregnancy. One other risk to the fetus is if the needle punctures the fetal blood vessel, it would result in bleeding. If the needle hits the fetus, it could result in lifelong scars. The risks to the mother are not very high, and the possible risks include puncturing the bladder or the intestine or blood vessels, and generally serious injuries are not caused. (Ethel Sloane, page 144)
Do the risks outweigh the benefits?
Whether or not the risks outweigh the benefits of amniocentesis is very subjective. It depends on what the mother feels. If a woman has been trying to conceive for a very long time, she will not want to take the risk of injuring the fetus by amniocentesis. On the other hand, if the mother has a history of genetic disorders running in the family, she will definitely find the benefits higher.
In my opinion, amniocentesis is certainly recommended especially for women over 35 years. It is better to be prepared and know about your child, so that adequate steps can be taken. When science and technology have advanced so much to provide us with better solutions, we make use of them to our benefit. If you are over 35 years and don’t conduct amniocentesis, and your child is predisposed to congenital metabolic disorders, it would be unfair and cruel to the child to bring him/her into this world where he will have to fight his syndrome daily and lead a torturous life.
The AMA council on scientific affairs and other scientific communities have been working on the “35 and over” policy for reconsidering the age and making amniocentesis more accessible to women.(Ethel Sloane, page 144)
Albert R. Jonsen, Robert M. Veatch, LeRoy Walters, Source Book in Bioethics
1998, Georgetown University Press, Washington D.C.
By Ethel Sloane,Biology of women, 4th Edition, 2002, Delmar, Thomson Learning