What is Cordocentesis, How is it done?
Cordocentesis, also known as fetal blood sampling or percutaneous umbilical blood sampling (PUBS), is a prenatal diagnostic procedure used to obtain a sample of fetal blood from the umbilical cord. This procedure is typically performed during the second or third trimester of pregnancy and is used to diagnose certain genetic disorders, infections, and blood disorders in the fetus.
The umbilical cord is a vital connection between the mother and the fetus, providing oxygen and nutrients to the developing baby. It consists of two arteries and one vein surrounded by a gelatinous substance called Wharton’s jelly. Cordocentesis involves the insertion of a thin needle into one of the umbilical cord vessels to withdraw a small amount of fetal blood for analysis.
The procedure is usually performed under ultrasound guidance to ensure accurate needle placement and minimize the risk of complications. Before the procedure, the mother’s abdomen is cleaned with an antiseptic solution, and a local anesthetic may be administered to numb the area where the needle will be inserted.
Once the area is prepared, the physician uses ultrasound to locate a suitable site for needle insertion. The needle is typically inserted into one of the umbilical cord veins, as they are larger and easier to access than the arteries. The needle is carefully guided into the selected vessel, and a small sample of fetal blood is withdrawn into a syringe.
After the blood sample is obtained, the needle is removed, and pressure is applied to the puncture site to prevent bleeding. The fetal blood sample is then sent to a laboratory for analysis, where it is tested for various genetic conditions, infections, and blood disorders.
Cordocentesis is considered an invasive procedure and carries some risks, although they are relatively low. The most common risks include bleeding from the puncture site, infection, and injury to the fetus or umbilical cord. However, these complications occur in less than 1% of cases.
The procedure is typically performed when other non-invasive prenatal tests, such as ultrasound or maternal blood tests, have indicated a potential problem with the fetus. Cordocentesis allows for more accurate and definitive diagnosis of certain conditions, as it directly samples fetal blood.
Some of the conditions that can be diagnosed through cordocentesis include chromosomal abnormalities like Down syndrome, genetic disorders such as cystic fibrosis or sickle cell disease, and certain infections like toxoplasmosis or rubella. It can also be used to assess fetal blood type and Rh compatibility between the mother and fetus.
In addition to diagnosis, cordocentesis can also be used for therapeutic purposes. In cases where certain blood disorders are detected, such as severe anemia or platelet disorders, the procedure can be used to administer blood transfusions or other necessary treatments directly to the fetus.
Overall, cordocentesis is a valuable tool in prenatal diagnosis and management. It allows for accurate and timely detection of certain fetal conditions, enabling healthcare providers to provide appropriate counseling and interventions. However, due to its invasive nature, the procedure is typically reserved for cases where the benefits outweigh the potential risks.