Patients over 35

First Trimester


Chorionic Villus



Amniocentesis is a procedure done to obtain a sample of the amniotic fluid from around the fetus. Amnotic fluid contains cells from the fetus that can be tested. The fluid can also be tested to determine if a neural tube defect such as spina bifida is present.

An amniocentesis is most commonly performed for one of the following reasons:

  • Maternal age 35 or older
  • Pregnant woman with an abnormal genetic screening test results (ie. AFP, cystic fibrosis)
  • Fetus with an abnormality detected by ultrasound
  • Previous child with genetic problem
  • Other family history of certain genetic problems

At Ocean Perinatology, all patients that are considered for an amniocentesis meet with one of our genetic counselors prior to the procedure to fully discuss the reasons for the amniocentesis, the risks involved, and options other than amniocentesis. The risk for pregnancy loss as a result of the procedure is approximately 1 in 200. Patients with twins and triplets usually require a separate amniocentesis for each fetal sac. The pregnancy loss rate for this situation (approximately 1 %) is higher than the rate of loss for a single amniocentesis. Other risks and side effects of the procedure include:

  • Cramping
  • Bleeding
  • Leaking of amniotic fluid
  • Infection
  • Direct fetal injury (extremely rare)

The procedure is performed at Ocean Perinatology in one of our ultrasound suites. A complete ultrasound is performed to assess the fetus for anomalies, determine the position of the placenta, and assess the amniotic fluid volume. A clear “pocket” of amniotic fluid within the sac around the fetus is identified and the maternal skin above this area is cleansed with iodine solution. A thin needle is then inserted into this clear pocket under the guidance of ultrasound and the fluid sample is removed. Only a small amount of the total amniotic fluid is removed (about 1 ounce) and it is rapidly replaced by the fetus. The entire procedure takes about 45 seconds.

The amniotic fluid is sent to the lab and the cells are grown for several days before testing. The tests that are done vary depending on the reason for the amniocentesis. All samples are evaluated to make sure that the fetal chromosomes are normal which effectively rules out disorders like Down Syndrome. All amniotic fluid is also tested for alpha-fetoprotein (AFP). This is a fetal protein that is normally found in amniotic fluid. Too much of it can be a sign of fetal defects such as spina bifida.

Amniocentesis procedures are performed daily at Ocean Perinatology. Our staff of highly trained perinatologists, genetic counselors and sonographers provide superior care to pregnant women facing the anxiety and difficult choices surrounding amniocentesis. If you have any questions or would like to schedule an appointment, contact us today.