Risks

Cordocentesis carries potentially serious risks, including:

• Fetal bleeding. Bleeding from the area where the needle is inserted is the most common complication. If life-threatening fetal bleeding occurs, your health care provider might recommend replacement of blood products to the fetus.

• Cord hematoma. A collection of fetal blood within the cord might occur during or after a cordocentesis. Most babies don't have signs or symptoms when this occurs. However, a few might develop a low heart rate for a short period.

  If the hematoma is stable, your health care provider will observe the baby. If the hematoma isn't stable or if your baby's heart rate doesn't recover, your health care provider will recommend an emergency cesarean delivery.

• Slowing of the baby's heart rate. The baby's heart rate might slow temporarily after cordocentesis.
• Infection. Rarely, cordocentesis can lead to a uterine or fetal infection.
• Fetal-maternal bleeding. Fetal blood might enter maternal circulation in about 40 percent of procedures. The amount of bleeding is usually small. This problem is more common when the placenta lies in the front of the uterus.
• Passing maternal infection. If the mother has certain infections, such as hepatitis B, hepatitis C or HIV, they might be passed to the baby.

• Pregnancy loss. Cordocentesis carries a higher risk of fetal death than do other prenatal diagnostic tests, such as chorionic villus sampling and amniocentesis. The risk is about 1 to 2 percent for a fetus that appears normal and is being tested for genetic disorders.

  However, since many babies are ill when the test is done, it's often difficult to determine whether fetal death is related to the procedure or to the baby's health.

Ultimately, the decision to have cordocentesis is up to you. Your health care provider and a genetic professional can help you weigh the risks and benefits.