1 What is a Cordocentesis?

Also known as percutaneous umbilical blood sampling (PUBS), cordocentesis is a prenatal diagnostic procedure that involves the extraction of a sample of a baby's blood from the umbilical cord for testing.

This procedure is usually performed on after the 18th week of pregnancy. The test can also be a tool in the detection of certain genetic disorders, blood conditions and potential infections.

This procedure can also be applied in the delivery of blood transfusions or medication to a baby through the umbilical cord.

The use of cordocentesis is declining, this is due to the development other procedures like amniocentesis and chorionic villus sampling, which have a lower risk of fetal loss.

However, cordocentesis might be offered if the other prenatal tests do not enough or sufficiently timely diagnostic information.

2 Reasons for Procedure

A patient will need to undergo a cordocentesis for the following reasons:

Cordocentesis is the primary method for the detection and treatment of blood conditions, such as fetal anemia.

Cordocentesis is usually turned to when another form of testing fail to reach a usable diagnosis.

Because carries a higher risk of fetal loss than methods, such as chorionic villus sampling or amniocentesis, your health care provider will only offer you the procedure as a last resort.

In rare cases, cordocentesis might be used to check the shape and number of fetal chromosomes (karyotype analysis).

Fetal blood karyotyping can be completed within a period of 48 hours, possibly providing results faster than amniocentesis or chorionic villus sampling.

3 Potential Risks

The following risks are related to cordocentesis:  

Fetal bleeding. Bleeding from the site of the needle insertion is the most popular risk of cordocentesis.

If baby life-threatening bleeding occurs, your health care provider might make a recommendation of blood product replacement to the fetus.

Cord hematoma. A collection of fetal blood within the cord might occur during or after the procedure. The majority of babies do not have any symptoms when this takes place.

However, a few might develop a low heart rate for a short period of time. If the hematoma is stable, your health care provider will observe the baby.

If the hematoma is not stable or your baby's heart rate does not recover, an emergency C-section will be recommended by your health care provider.

The slowdown of your baby's heart rate. The heart rate of your baby might slow down temporarily after cordocentesis.

Infection. In rare conditions, cordocentesis can result in uterine or fetal infection. Fetal-maternal bleeding. In 40 percent of the procedures, fetal blood might enter the mother's circulation.

The quantity of bleeding is usually small. This risk is higher if the placenta is located in front of the uterus.

Pregnancy loss. Cordocentesis carries a larger risk of fetal loss than any other method of prenatal diagnosis, such as chorionic villus sampling and amniocentesis.

The risk as approximately 1.4 to 1.9 percent for a fetus that appears to be normal and is being tested for genetic disorders.

However, since a lot of babies are ill when the test is done, t is often quite difficult to determine whether the fetal loss is related to the procedure itself of the health of the baby.

4 Preparing for your Procedure

In preparing for your cordocentesis, you must follow your doctor’s orders.

If you have had the pregnancy for 24 weeks, you will be asked to stay away from eating or drinking after midnight the night prior to your procedure.

This is usually because certain complications caused by the procedure can lead up to an emergency C-section. Ask your health care provider for guidance.

You might also want to ask your partner or close relation to accompanying you to your appointment for emotional support or just to drive you home after the cordocentesis.

5 What to Expect

Here’s what you can expect before, during, and after your cordocentesis.

Prior to the 24th week of pregnancy, cordocentesis is usually done in an outpatient facility or in the office of a health care provider.

Following the 24th week of pregnancy, this procedure is commonly done in a hospital. A minimum of one assistant will likely aid your health care provider during the cordocentesis.

A sample of your blood is usually taken prior to the procedure for comparison with the fetal blood samples.

During the procedure. In a period of about 30 minutes to an hour before the procedure, you might be given antibiotics in order to decrease the risk of any uterine infection.

This is commonly performed through an intravenous tube known as a catheter. As the procedure is commenced, your health care provider uses ultrasound to pinpoint the exact location of your baby in the uterus.

You will lie on your back on an examination table, and your health care provider will proceed to apply a special kind of gel to your abdomen.

Furthermore, he or she will use a small device called a transducer to show your baby's position on a monitor. After this, your health care provider will your abdomen with an antiseptic.

In some cases, local anesthesia is used to ease the discomfort, but it is often not required. With the ultrasound as a guide, your health care provider will proceed to insert a thin and hollow needle through your abdominal wall into your uterus.

A small quantity of blood from a vein in the umbilical cord will be extracted through the syringe. The needle is then removed. Try to avoid making any movements during the process of insertion and extraction.

You might take notice of a stinging sensation as the needle pierces your skin, and you might also feel some cramping when the needle enters our uterus.

After the procedure. After the blood sample has been extracted, you might feel some cramping and a small amount of discomfort.

An ultrasound or an external labor monitor will then be used to monitor your baby's heart rate after the procedure.

When you leave the hospital, your health care provider might make a suggestion of resting for the remainder of the day. You will likely be capable of resuming your normal day-to-day activities the following day.

Your health care provider will also ask you to contact him or her if you have any signs and symptoms, such as vaginal bleeding or fluid leakage.

Meanwhile, the blood sample will be taken to the lab for analysis. Test results are usually available in a few days.

6 Procedure Results

Understanding the results of your cordocentesis will be made possible by your health care provider or by your genetic professional.

Your health care provider will share with you information that concerns follow-up appointments if your test results turn up to be normal.

In cases where your baby has an infection, your health care provider will be very helpful in making you understand your treatment options.

If your baby is suffering from anemia, a blood transfusion through the umbilical cord might be required.

If the test results show that your baby has an untreatable condition, you might have to deal with a wrenching decision, such as whether to continue the pregnancy.

In these moments, it is advisable to seek encouragement from members of your health care team, your loved ones and other close contacts.