Fetal scalp blood testing

Fetal scalp blood testing is a technique used in obstetrics during active labor to confirm whether a fetus is receiving enough oxygen. This is a supplementary procedure used to determine if fetal acidemia has occurred following fetal cardiac distress.^[1] While continuous fetal heart rate monitoring is the primary method for assessing fetal wellbeing during labor, a change in fetal heart rate is not indicative of fetal acidemia.^[1][2] Some of the signs and symptoms of oxygen deprivation are pH in the umbilical cord, abnormal fetal heartbeat and abnormal coloration of amniotic fluid.^[3][4] This correlation can only be concluded by sampling fetal scalp blood and measuring acid status.^[1] Therefore, fetal scalp blood testing could be used to reduce the number of unnecessary emergency caesarean sections made on the decision of fetal heart rate alone.^[1]

Fetal blood sampling is a useful procedure that can diagnose, treat, or monitor different fetal problems. With the help of a small needle, various providers and specialists can remove small amounts of blood from the fetus. This procedure is used to help determine blood type, diagnose genetic abnormalities, identify fetal infections, fetal anemia, and low platelet count. With the help of continuous ultrasound guidance to place the needle in the abdomen into the tiny fetal blood vessel, the blood sample gets obtained and sent for testing.^[5] Therefore, due to limitation in adding value, fetal scalp testing can serve as second line test to provide and strengthen the information on fetal acidosis and hypoxia status obtained from cardiocotography (CTG).^[6][7] Cardiocotography is the primary means of monitorning a fetus during pregnancy as well as labour.^[4]

Fetal blood sampling is a complex procedure and performed when other tests are not possible. It can be done for pregnancies that are 18 weeks or later. The procedure has many benefits such as providing specific information about the baby's health and the ability to treat babies with any severe blood diseases before birth. Potential risks include bleeding from the fetal blood sampling site, infection, changes to heart rate, and death.^[8]