Fetal Blood Sampling (FBS) During Pregnancy

Overview

Fetal blood sampling (FBS) is the collecting of fetal blood directly from the umbilical cord or fetus. The fetal blood is tested for signs of anemia and other blood problems. FBS is also known as cordocentesis or percutaneous umbilical cord blood sampling.

FBS is usually used when a Doppler ultrasound and/or a series of amniocentesis tests have first shown moderate to severe anemia.

If you are Rh-sensitized and you are carrying an Rh-positive fetus, your immune system can attack the fetus's red blood cells. FBS is used to look at a fetus's red blood cell count and oxygen level. It also looks for signs that your immune system is destroying fetal red blood cells.