Amniocentesis

Details

Published on Thursday, 06 October 2011 07:09

Written by Ginny

Amniocentesis 

Amniocentesis is a procedure where a sample of fluid is removed from around the baby for analysis. The amniotic supports the bay in many ways. It keeps baby in a completely buffered environment. It is full of fetal cells, proteins, and fetal urine. For genetic testing, chromosome analysis, and evaluation of an abnormal AFP test, amniocentesis is usually performed between the 15th and the 20th weeks of pregnancy.

How is it done?

During amniocentesis, fluid is removed by placing a long needle through the abdominal wall into amniotic sac. Sometimes, the woman's skin is injected first with a local anesthetic, but this is sometimes not necessary. Through the procedure an ultrasound is used to guide the needle into the correct part of the amniotic sac. Once the needle is in the sac, a syringe is used to withdraw the clear amber-colored amniotic fluid, resembling urine. The amount of fluid withdrawn depends upon the age of the fetus and the reason for the testing.

The fluid will then be sent for genetic analysis, fetal lung maturity, and any evidence of neural-tube defects such as spina bifida. Any infection present will also be detected. The chromosomes are then extracted and analyzed. It takes about two weeks to perform chromosome analysis.

Risks and Results 

For most patients, amniocentesis is a fairly quick and comfortable procedure. Some women experience some uterine cramping or a feeling of faintness. Overall, amniocentesis is a safe procedure with the risk of fetal loss at generally less than 1%. According to the American College of Obstetricians and Gynecologists Practice Bulletin, there is a procedure-related rate of fetal loss ranging from 1/300 to 1/500 procedures. The results for some things such as spina bifida will be available in 2 – 3 days. The other chromosome results will be available in 11 -14 days.