Cordocentesis: Procedure, Risks & Benefits in Pregnancy

What Is Cordocentesis?

Cordocentesis is a prenatal test where a small sample of the baby's blood is taken from the umbilical cord. This allows the blood to be tested for genetic conditions, infections, blood disorders and other health issues. The medical term for cordocentesis is percutaneous umbilical blood sampling, or PUBS test.

Why Is Cordocentesis Performed?

The main cordocentesis purpose is to diagnose or rule out certain foetal health problems. Your doctor may recommend cordocentesis if:

• You had an abnormal result from another prenatal screening test
• You have a family history of genetic disorders
• You've been exposed to an infection that can harm the foetus
• Foetal development appears abnormal on ultrasound
• Foetal anaemia or other blood disorders are suspected

What does cordocentesis test for?

Cordocentesis can be used to test for a range of foetal health issues, including:

• Chromosomal abnormalities like Down syndrome
• Blood disorders such as anaemia, thrombocytopenia or Rh incompatibility
• Infections like toxoplasmosis, cytomegalovirus or rubella
• Metabolic disorders like galactosemia or phenylketonuria
• Foetal oxygen levels and blood pH (acidity)

How Is the Cordocentesis Procedure Done?

The cordocentesis procedure involves the following steps:

• Ultrasound is used to locate the umbilical cord and guide the needle.
• A thin needle is inserted through the mother's abdomen into a vein in the umbilical cord.
• A small sample of foetal blood is withdrawn.
• Once the sample is collected, the needle is removed and your baby’s heart rate is monitored.

The whole procedure usually takes about 20-30 minutes. You will need to lie still during the procedure.

What can I expect during cordocentesis?

During cordocentesis, you can expect to:

• Have your belly cleaned with an antiseptic solution
• Receive local anaesthesia to numb the needle insertion site
• Feel some pressure and mild discomfort as the needle enters
• Have foetal heart monitoring before and after the procedure
• Rest for a few hours after the test

Your healthcare provider will give you specific instructions on how to prepare and what precautions to take afterwards.

What can I expect after cordocentesis?

After the cordocentesis procedure, you'll be monitored for a short time to make sure you and the baby are doing well. Most women can go home the same day. You may experience some mild cramping or spotting, which is normal.

However, contact your doctor immediately if you have:

• Heavy bleeding or fluid leakage from the vagina
• Severe abdominal pain or cramping
• Fever or chills
• Redness or swelling at the needle site
• Decreased fetal movement

What Are the Risks of Cordocentesis?

While cordocentesis provides valuable diagnostic information, it's important to be aware of the cordocentesis risks.

These include:

• Miscarriage (1-2% risk)
• Foetal bleeding or blood loss
• Infection
• Preterm labour
• Temporary changes in foetal heart rate
• Maternal Rh sensitisation in Rh-negative women

The cordocentesis risk is higher than for other prenatal tests like amniocentesis. Therefore, it's only done when absolutely necessary, and the benefits outweigh the risks.

What Results Can You Expect from a Cordocentesis Test?

Cordocentesis results are usually available within a few days. The specific results will depend on what the blood is being tested for.

In general, the cordocentesis results can help:

• Diagnose or rule out foetal health problems
• Determine if the baby needs a blood transfusion or other treatment
• Guide decisions about pregnancy management and delivery timing
• Provide reassurance if results are normal

Your healthcare provider will explain what the results mean for you and your baby.

When Is Cordocentesis Recommended During Pregnancy?

Cordocentesis is typically done after 18 weeks of pregnancy, in the late second or third trimester. It's only recommended when the benefits of the information gained outweigh the risks of the procedure.

Specific reasons to consider cordocentesis include:

• Abnormal results from previous screening tests
• Known or suspected foetal health problems
• Need for rapid prenatal diagnosis of certain conditions
• Foetal treatment like blood transfusions is required

How to Prepare for a Cordocentesis Procedure

To prepare for a cordocentesis procedure, follow these tips:

• Schedule the procedure at a reputable centre with experienced professionals
• Arrange for someone to drive you home afterwards
• Avoid eating or drinking for 8 hours before the test, if advised
• Inform your doctor of any medications or supplements you take
• Discuss the cordocentesis purpose, process and risks with your provider
• Have your blood type and Rh factor checked
• Rest and avoid strenuous activity for 24 hours after the procedure

Cordocentesis vs. Amniocentesis vs. CVS: What's the Difference?

Here's a quick comparison of cordocentesis with two other prenatal diagnostic procedures:

Cordocentesis is done later than amniocentesis and CVS. It also has a higher miscarriage risk (1-2%) compared to amnio (0.1-0.3%) and CVS (0.5-1%). However, it provides faster results and is used when other tests are inconclusive or foetal blood is specifically needed.

Final Thoughts: Is Cordocentesis Right for You?

While cordocentesis provides valuable information, it's a complex decision that requires careful consideration of the cordocentesis purpose, cordocentesis procedure, and cordocentesis risks. Discuss the pros and cons thoroughly with your healthcare team to determine if the benefits outweigh the risks in your unique situation.

If you do opt for prenatal testing, know that Metropolis Healthcare is here to support you. Our expert technicians can collect your samples in the comfort of your home. We'll process the tests in our state-of-the-art labs and provide you with accurate, reliable results to guide your pregnancy care. Remember, staying informed and proactive about your prenatal health is key to giving your baby the best start in life.

FAQs

When is cordocentesis performed?

Usually after 18 weeks, in the late second or third trimester.

Who performs the cordocentesis procedure?

A perinatologist (high-risk pregnancy specialist) or obstetrician with special training.

Is cordocentesis invasive?

Yes, it involves inserting a needle into the uterus and umbilical cord.

When should I know the cordocentesis results?

Usually within 1-3 days, depending on the specific tests done.

What is the benefit of a cordocentesis?

It provides detailed diagnostic information to guide pregnancy care decisions.

At what stage of pregnancy is cordocentesis performed?

Cordocentesis is typically done between 18 and 24 weeks of pregnancy.

What conditions can cordocentesis detect?

It can detect genetic disorders, infections, blood conditions, and foetal anaemia.

Do I need to fast before cordocentesis?

No fasting is required; you can eat and drink normally before the procedure.

How long do cordocentesis results take?

Results usually take a few days to two weeks, depending on the tests performed.

Can cordocentesis harm the baby?

While generally safe, it carries a small risk of miscarriage, infection, or bleeding.