Amniocentesis is a medical procedure used primarily in the prenatal diagnosis of chromosomal abnormalities and fetal infections of the fetus. A routine carrier screening is conducted by using a needle to remove a small amount of amniotic fluid from the amniotic sac containing fetal cells and important proteins, this test can also determine the sex of the unborn baby. During pregnancy, the unborn baby grows inside the amniotic sac and the amniotic fluid surrounds and protects the baby inside the mother’s womb.

It is done by inserting a hollow needle through the abdominal wall into the uterus of a pregnant female, for extracting fluid from the amniotic sac for studying the cells that contain genetic information to diagnose mild to severe abnormalities. Diagnosing inherited diseases, disorders and other health anomalies can help understand further complexities that can crop up during pregnancy and after childbirth. The procedure is generally carried out in the 15th to 17th week of gestation and is relatively painless. Although as many as 50 metabolic disorders and diseases can be diagnosed by use of this procedure, it is mostly done for the identification of chromosomal anomalies and neural tube defects that develop very early during pregnancy.

Also Read: Genetic Testing: What Is It, How It Is Done And What To Expect?

Who Gets Amniocentesis Done?

Healthcare provider recommends amniocentesis during pregnancy when:

  • An ultrasound detects a possibility of abnormality in the fetus
  • A prenatal screening test detects an increased risk for a chromosome disorder
  • The pregnant woman has a history of three or more abortions
  • The mother is older than 35 at the time of delivery. Mothers over thirty-five years of age stand a higher chance of having a baby with a chromosomal disorder
  • Certain genetic disorders like sickle cell disease, Down syndrome, Tay-Sachs disease, or cystic fibrosis run in the family, or the mother is found a carrier of a genetic disorder
  • A life-threatening condition where the baby and the pregnant mother have different blood Rh types is observed.

Also Read: Down Syndrome: Causes, Symptoms And Treatment

How Is Amniocentesis Performed?

A short process, amniocentesis is done by an obstetrician. After a thorough cleaning of the belly area to disinfect, a gel is applied, and an instrument is run over the gelled area that captures ultrasound images of the baby. The obstetrician then carefully inserts a needle into the amniotic sac to remove a small amount of fluid through the needle. The process is slightly uncomfortable with menstrual-like cramping during the procedure that can last for a few hours. The extracted fluid sample is sent to a laboratory where the baby’s cells are separated from the amniotic fluid for analysis. The cells are kept growing for about two weeks and then tested for neural tube defects and other anomalies.

Results Of Amniocentesis

The time it takes to receive the results depends on what tests need to be performed on the amniotic fluid. More often, the complete test results are available in about two weeks. The accuracy of amniocentesis is as accurate as ninety-eight percent in detecting abnormalities, but the test doesn’t measure the severity of any disorder. If amniocentesis results show that the baby has a specific health abnormality, the healthcare provider refers you to a neonatologist who can discuss specific treatments, surgeries, or medications the baby might need.

Risks Of Amniocentesis

Most amniocentesis procedures are potentially safe, and complexities are rare. But amniocentesis does present small risks for the baby and mother. In fewer (about one percent) cases, amniocentesis leads to miscarriage or early delivery. Some other complications of amniocentesis are:

  • Cramping
  • Amniotic fluid leakage
  • Injury or infection
  • Bleeding
  • Spotting
  • Loss of pregnancy in extreme cases
  • Premature labor

Difference Between Amniocentesis And Chorionic Villus Sampling

CVS or chorionic villus sampling is a genetic disorder identification test to diagnose genetic conditions during pregnancy. CVS testing takes a small sample of cells from the placenta and is performed earlier in pregnancy that is at 10 to 13 weeks while amniocentesis happens after 15 weeks. Amniocentesis can identify neural tube defects besides other tests, but CVS can only test Down syndrome, Trisomy 21, Cystic Fibrosis, Sickle cell disease, Tay-Sachs disease, and Edward syndrome. It does not detect certain birth defects, heart problems, cleft lip, and spina bifida.