Fetal blood sampling is  a procedure  to remove a small amount of  blood from the fetus during  pregnancy. In the past, this procedure was used only during labor through the mother’s open cervix to test blood from the fetal scalp for oxygenation. The procedure is usually done by specialized trained  perinatologist, a doctor who specializes in the care of the fetus in high risk pregnancies. It is done as part of diagnosing fetal problems  at various times of pregnancy.

It can be done in the following situations :

• Diagnose genetic or chromosomal abnormalities
•  Check fetal oxygen levels
• Check for and treat  severe fetal anemia  or other blood problems such as Rh disease
• Check for fetal infections
• Give certain medications to the fetus

How is fetal blood sampling done ?

There are several ways to obtain fetal blood sample.After cleansing the mother’s abdomen with antiseptic, a long, thin needle is inserted into the mother’s uterus guided by ultrasound. Blood may then be taken from the flowing sources.

• Blood vessels of the umbilical cord. This is known as cordocentesis, or percutaneous umbilical blood sampling, or PUBS.
• A fetal blood vessel usually in the liver or heart.

What are the risks and benefits of fetal blood sampling ?

The procedure is very complex and must be done by a trained doctor. It is used when other tests and procedures are not possible or effective . It can be performed for pregnancies that are 18 weeks or older.

Benefits

• It can be used to obtain specialized information about the health of the fetus.
• Fetuses with severe blood damaging diseases can be treated before birth.

Risks

• Changes in the fetal heart rate
• Leaking of the amniotic fluid
• Bleeding from the fetal blood sampling site
• Infection
• Fetal death