Fetal scalp electrodes may be attached only after the neck of the womb has dilated to at least 2 cm
Fetal scalp electrodes may be attached only after the neck of the womb has dilated to at least 2 cm, and the amniotic sac (the bag of water around the fetus) has ruptured. A sensor is usually strapped to the mother’s thigh. A thin wire (electrode) from the sensor is put through the womb (uterus). The electrode is then attached to the baby's scalp to monitor the baby’s heartbeat. A small tube (catheter) that measures contractions may be placed in the womb next to the baby. The strength and timing of your contractions are often printed out on a chart. A normal fetal heart rate range is 115-150 beats per minute.
- A slow heart rate may indicate the baby is not getting enough oxygen delivery to the brain.
- A fast heart rate may indicate oxygen deprivation.
- Variable decelerations are irregular dips in the fetal heart rate that may indicate cord compression, a potentially dangerous condition for the baby.
- Late decelerations begin with a womb contraction and continue for too long after the contraction has resolved. This may be a sign that the baby is distressed.
Using fetal scalp electrodes may provide an accurate condition of the baby during labor.
What happens if the fetal heart rate is not normal?
If the baby’s heart rate is not normal doctor may follow the below steps:
- May give mother oxygen supplementation to breathe
- May change the mother’s position
- Start intravenous (IV) fluids
- Give medicine to stop or slow the contractions or to lessen their strength
- Deliver the baby right away with forceps or vacuum extraction
- Deliver the baby by cesarean delivery
What are the possible risks involved during attaching the fetal scalp electrode?
The risks of the procedure include:
- The electrode may cause an infection in the baby
- Improper placement of the electrode may injure the baby
- The catheter put into the uterus may cause bleeding if it goes through the placenta or the womb wall, or it may cause an infection in the uterus.
When does a doctor recommend the fetal scalp electrode?
Doctors usually recommend a fetal scalp electrode due to the below reasons:
- If the mother has a problem during pregnancy or labor, the doctor may need continuous fetal heart rate monitoring to observe the baby’s condition
- When the doctor wants to measure the strength of your contractions
- When the external monitor (placed on the mother’s belly) is not recording accurately
- When it is a high-risk pregnancy
- When the mother has an illness, such as diabetes or high blood pressure
- When the mother is given the drug Oxytocin that helps stimulate and strengthen the contractions
When is the fetal scalp electrode not recommended?
The membrane and fluid, called the bag of water or amniotic fluid, surrounding the baby must be broken to put the instruments into the uterus. For this reason, there are times when the doctor may not use fetal scalp electrode:
- When the placenta is covering the opening to the womb (a condition called placenta previa)
- When the baby is too high in the womb and breaking the bag of waters could be dangerous
- When the mother has a severe infection, such as herpes or HIV, the doctor may not use a fetal scalp electrode. Using an internal monitor could increase the chance of spreading the infection to the baby.