This is a test in which a sample of blood is obtained from the fetus (unborn baby) by placing a needle in a blood vessel within the umbilical cord. Ultrasound is used by the physician to guide the needle to the umbilical cord. This procedure should be done at a center that is experienced in the procedure, such as Ohio State University.
A blood sample from the fetus might provide useful information that is needed to guide the care of certain pregnancies. Some examples of laboratory tests that may be obtained on the fetus are:
- Red blood cell count to check for anemia
- Platelet count
- Thyroid function tests
- Chromosomal testing (An amniocentesis is more commonly used to obtain chromosomes, but cordocentesis might be recommended in some special cases.)
There is a small risk that the bag of waters around the fetus could break or that the procedure could cause labor. These risks are always compared to the possible benefits from the information that will be gained from the fetal blood sample before a decision is made whether to proceed.
Pain medicines are used to keep the mother and baby comfortable. The medicines are safe for the baby to receive. Usually, the mother is in the hospital for a couple hours and goes home the same day.