A Look at Amniocentesis


 Amniocentesis is a test that your doctor will use to try to gather certain information about the health of your baby. It involves taking a sample of the fluid surrounding your baby inside the uterus, known as amniotic fluid.

Most of the time, a woman undergoes amniocentesis in order to decide whether her baby has a chromosomal or genetic abnormality. Very often, it’s used to test for Down Syndrome. Amniocentesis is usually done between weeks 16 and 22 of pregnancy.

Here are some of the reasons that amniocentesis is performed:

  • To look at your baby’s lungs if an early delivery is being considered due to medical reasons.

  • To look for the presence of a uterine infection, which can be harmful to both you and your baby.

  • To examine whether your baby is all right in a situation in which you have Rh sensitization. Rh sensitization can occur when your blood type is different from your baby’s. (More and more, however, doctors are using Doppler ultrasound for this situation instead of amniocentesis.

There are a number of defects or disorders that amniocentesis can check for, including:

  • Down Syndrome, as mentioned above.

  • Other chromosomal orders like trisomy 13 and sex chromosome abnormalities like Klinefelter syndrome. Amniocentesis is nearly 100% accurate at detecting these disorders.

  • Identifying other genetic disorders such as sickle cell disease and cystic fibrosis. There are actually several hundred disorders on the list that amniocentesis can identify.

  • Neural tube defects including conditions like anencephaly and spina bifida.

There are a number of birth defects that can’t be discovered through the amniocentesis procedure, including things like a malformation of the heart or a cleft palate. However, many of these conditions can be identified during an ultrasound.

There is some risk of a miscarriage with amniocentesis, and therefore it’s not necessarily a routine procedure. While the risk is less than 1%, for most women it’s not necessary unless there is a specific reason to believe that there might be a problem with your baby or your pregnancy.