Cordocentesis is also known as percutaneous umbilical cord sampling PUBS. It is  a diagnostic test that checks  the blood of the developing fetus for any abnormalities. This procedure can also be used to deliver blood transfusions and medications to the baby. Cordocentesis is usually performed at 17 weeks  gestation. It is usually done when a diagnostic information cannot be obtained from a CVS, amniocentesis  or ultrasound.

How is a Cordocentesis  performed ?

During this procedure, an ultrasound is used as a guide. It locates  where the umbilical cord inserts into the placenta. The ultrasound guides the needle through the abdomen and uterine wall and into the placenta. The needle is then used to take a sample of fetal blood. The blood sample is sent to the lab for analysis. Lab results are usually back in 72 hours. The procedure is similar to an amniocentesis except that in this case, the blood is taken from the fetus as opposed to the amniotic fluid.


What does a Cordocentesis look for ?

This test detects chromosomal abnormalities such as Down syndrome and blood disorders such as fetal hemolytic disease. The test is done to diagnose the following conditions :

  • fetal anemia
  • malformations in the fetus
  • fetal infections such as toxoplasmosis and rubella
  • isoimmunisation
  • fetal platelet count in the mother

This test does not allow testing for neural tube defects unlike an amniocentesis.


Are there any risks ?

This is an invasive test and therefore pose some potential risk such as

Contact your health care provider if you experience fever, chills and amniotic fluid leakage.


What do the results mean ?

This diagnostic test can detect chromosome abnormalities and certain blood disorders with high levels of accuracy. The test does not however measure the severity of the abnormalities and cannot identify neural tube defects.


Further testing is optional. However it provides you the opportunity to make a diagnosis and get potential intervention such as surgery that may be available for the baby. It may also help you  prepare emotionally and physically for taking care of a child with special needs.


Some individual may opt out if further testing due to personal, moral, or religious reasons.


It is important to discuss the benefits and risks of testing with your health care provider.
Content Sources

Cordocentesis : Percutaneous Umbilical Blood Sampling (PUBS) . American Pregnancy Association. Accessed January 2, 2015
Cordocentesis. Mayo Foundation. Accessed January 2, 2015
Cordocentesis . Birth. Accessed January 2, 2015

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