Cordocentesis is a diagnostic test that examines blood from the fetus to detect fetal abnormalities.
How is cordocentesis performed?
An advanced imaging ultrasound determines the location where the umbilical cord inserts into the placenta. The ultrasound guides a thin needle through the abdomen and uterine walls to the umbilical cord. The needle is inserted into the umbilical cord to retrieve a small sample of fetal blood. The sample is sent to the laboratory for analysis, and results are usually available within 72 hours.
The procedure is similar to amniocentesis except the objective is to retrieve blood from the fetus versus amniotic fluid.
When is cordocentesis performed?
Cordocentesis is usually done when diagnostic information can not be obtained through amniocentesis, CVS, ultrasound or the results of these tests were inconclusive. Cordocentesis is performed at 18 weeks or after.
What does the cordocentesis test look for?
Cordocentesis detects chromosome abnormalities (i.e. Down syndrome) and blood disorders (i.e. fetal hemolytic disease.). Cordocentesis may be performed to help diagnose any of the following concerns:
This test is different from amniocentesis in that it does not allow testing for neural tube defects.
What do cordocentesis results mean?
Cordocentesis is a diagnostic test that detects chromosome abnormalities and certain blood disorders with high levels of accuracy. Although the probabilities of identification are high, this test does not measure the severity of these disorders. This test also does not help identify neural tube defects.
What are the risks and side effects to the mother or baby?
Although cordocentesis is considered to be a safe procedure, it is recognized as an invasive diagnostic test that does pose potential risks. Miscarriage is the primary risk related to cordocentesis occurring between 1 to 2 times out of every 100 procedures.
Other potential side effects include:
Contact your healthcare provider if these symptoms remain or get worse. You should also contact your healthcare provider if you experience:
What are the reasons to test or not test?
The reasons to test or not test vary from person to person, couple to couple and physician to physician. Performing the tests and confirming the diagnosis provides you with certain opportunities:
Some individuals or couples may elect not to pursue testing or additional testing for various reasons:
It is important to discuss the risks and benefits of testing thoroughly with your healthcare provider. Your healthcare provider will help you evaluate if the benefits from the results could outweigh any risks from the procedure.
Reprinted with permission from American Pregnancy Association