Amniocentesis is a test that is done during a woman’s pregnancy to check information about the fetus. A fetus is generally known as a developing human, in utero, after the 8th week of gestation during a woman’s pregnancy. This procedure is done to determine if the fetus has any genetic problems such as spina bifida, anencephaly, Rh disease, or an open neural tube defect in the umbilical wall. Spina bifida is a birth defect in which the backbone and spinal canal do not close before birth.
Anencephaly is an absence of the large part of the brain and skull. Rh disease causes hemolytic disease of a newborn baby. An open neural tube defect is an abnormal formation of the neural tube during embryonic development. Amniocentesis also checks the levels of alpha-fetoprotein which is a protein produced by the yolk sac and liver during fetal life. Bilirubin is naturally found in amniotic fluid. It is a yellowish pigment found in bile.
During a normal pregnancy, the levels increase until 23 to 25 weeks of pregnancy and decrease as pregnancy continues. Low levels of this may also cause problems during the development of the fetus. Amniocentesis is usually done during the second trimester of a woman’s pregnancy. The first step in this process is to do an ultrasound of the fetus. An ultrasound is inaudible sounds in frequency ranging from 20,000 to 10 billion. Once the abdomen has been cleaned, a doctor will insert a needle into the uterine wall where the fetus grows.
Once the needle has passed the uterine wall in then reaches the amniotic sac where the fetus grows in amniotes. A doctor will then begin to remove approximately 20 ml of amniotic fluid for testing. Once the fluid has been removed the fluid is then sent off to a laboratory to be analyzed and checked for any abnormalities. Amniocentesis can be occasionally unsuccessful due to technical issues including the inability to collect enough amniotic fluid or failure of the collected cells to grow once cultured. Accuracy of Amniocentesis is about 99. 4%.