Cordocentesis

What is cordocentesis?

Cordocentesis is a prenatal test that takes a sample of blood from a fetus’s umbilical cord to detect abnormalities. It can diagnose certain problems before a baby is born, such as genetic mutations (changes), blood diseases and infections. In addition, the procedure can deliver medications or blood transfusions to a fetus through the umbilical cord.

It’s also called percutaneous umbilical cord blood sampling (PUBS) or funipuncture.

Why is cordocentesis performed?

Routine prenatal testing includes prenatal ultrasonography and blood work. If noninvasive prenatal testing reveals a possible problem, your healthcare provider may recommend invasive testing, such as amniocentesis or chorionic villus sampling.

If results still aren’t clear, your healthcare provider may suggest cordocentesis.

What does cordocentesis test for?

The test can help diagnose certain conditions in a fetus:

• Anemia, a low number of healthy red blood cells.
• Thrombocytopenia, a low number of platelets (blood particles that help with clotting).
• Blood disorders such as fetal hemolytic disease, when red blood cells break down quickly.
• Chromosomal abnormalities (inherited or random genetic mutations), such as Down syndrome.
• Infection, such as toxoplasmosis or rubella.
• Isoimmunization, when a pregnant person’s blood isn’t compatible with the fetus’s.

When is cordocentesis performed?

Healthcare providers perform cordocentesis any time after the 17th week of pregnancy.

Who performs the cordocentesis procedure?

The procedure occurs in an office or hospital, usually by an obstetrician, a specialist in pregnancy and childbirth.

Is cordocentesis invasive?

Cordocentesis is an invasive procedure. It’s used only after other types of testing don’t provide enough information.

How do I prepare for cordocentesis?

Your healthcare provider will give you specific instructions to help you prepare for the test. You may have to fast (avoid food and drink, other than water) for several hours in case cordocentesis leads to an emergency C-section.

Your healthcare provider may give you IV antibiotics before the procedure to help prevent infection. They also may take a sample of your blood so they can compare it to the fetus’s blood.

Consider asking a loved one to come to the appointment. They can provide emotional support and drive you home afterward.

What can I expect during cordocentesis?

To perform cordocentesis, a healthcare provider will:

• Ask you to lie down on an exam table and stay still.
• Clean your belly.
• Perhaps administer anesthesia to an area of skin on your abdomen to prevent pain.
• Apply a gel to your belly and use ultrasound technology to see inside. This will help determine the baby’s position and the location of the umbilical cord to safely guide the procedure.
• Insert a needle through your abdomen into a blood vessel in the umbilical cord. This may sting or create a feeling of pressure or cramping.
• Use the needle to draw a small sample of blood.
• Remove the needle.
• Send the sample to a lab for testing.

Cordocentesis can also deliver medications or treatments. For example, if a fetus has anemia, the procedure can deliver a blood transfusion.

What can I expect after cordocentesis?

After cordocentesis, your healthcare provider may monitor the fetal heart rate for a short period of time.

You may experience cramping or feel a bit uncomfortable after the test. Consider taking it easy for the rest of the day.

What are the risks of cordocentesis?

Percutaneous umbilical blood sampling is an invasive procedure with significant risk. It can cause miscarriage in about 1 or 2 of every 100 procedures. The test also sometimes leads to early delivery by emergency C-section.

Other risks include:

• Blood loss in the fetus or the mother.
• Cord hematoma, when blood collects in the umbilical cord.
• Slow fetal heart rate.
• Infection in the fetus or uterus.
• Premature rupture of membranes, which may lead to early delivery.
• Separation of the placenta from the uterus.

When should I know the results of cordocentesis?

The results of cordocentesis are usually available in a few days.

What do the results of cordocentesis mean?

Your healthcare provider and perhaps a genetic counselor will help you understand the results of cordocentesis.

If the results are normal, you may still need several follow-up appointments to monitor your health and the fetus’s health.

If cordocentesis detects a problem, your healthcare provider will discuss treatment options, which vary widely, such as:

• Medicine to treat infection (antibiotics or antivirals).
• Blood transfusions to the fetus.
• Termination of the pregnancy if treatment isn’t possible.

When should I call my healthcare provider after cordocentesis?

After cordocentesis, call your healthcare provider if you experience:

• Chills.
• Cramps that don’t get better throughout the day.
• Decreased fetal movement.
• Fever.
• Leaking of amniotic fluid.
• Vaginal bleeding.

A note from Cleveland Clinic

Cordocentesis is an invasive prenatal procedure. It’s performed to take a sample of blood from a fetus’s umbilical cord to detect certain abnormalities. It can also deliver medications and blood transfusions when needed. If you’re concerned about your fetus’s health, talk to your healthcare provider about the risks and benefits of prenatal testing.