It is always exciting to hear your baby’s heartbeat during routine antenatal visits. The fast clip clopping that sounds so much like a horse galloping away is a wonderful affirmation of the life growing inside your belly.
During labour it can be a handy tool to monitor the baby’s well-being as he or she passes through the narrow curvy birth canal. . By listening to, or recording the baby’s heartbeat, it is hoped to identify babies who are becoming short of oxygen (hypoxic) and who may benefit from some form of intervention.
It goes without saying that in our present climate of risk adverse medicine with over use of technology, it is important to understand how and why fetal monitoring is used in order to avoid MISUSE and UNNECESSARY intervention.
There are 3 Common Ways to Monitor the Fetal Heart Rate
- External fetal monitoring or CTG (cardio toco graph) – two stretchy bands with two transducers are placed on the abdomen. One transducer records the fetal heart rate using ultrasound and the other transducer monitors the contractions of the uterus by measuring the tension of the maternal abdominal wall. This is often done for 20 minutes on admission to the L&D to get a baseline recording. It is also often used continuously throughout labour to monitor fetal heart rate and contractions.
- Doppler fetal heart rate monitor – a hand-held ultrasound transducer used to detect the heartbeat of a fetus using the Doppler effect to provide an audible simulation of the heartbeat, This is usually done intermittently during labour – preferably before, during and after a contraction. (every 15-30 minutes in active labour and every 5-15 minutes during second stage)
- Internal Fetal Scalp Electrode Monitoring – A wire electrode is attached to the fetal scalp through the cervical opening and is connected to the monitor. Internal monitoring may be used when external monitoring of the fetal heart rate is inadequate, or closer surveillance is needed.
Why Do You Need Fetal Heart Rate Monitoring?
Strong uterine contractions during labour reduce the flow of maternal blood to the placenta. The umbilical cord may also be compressed, especially if the membranes are ruptured. Usually the baby has sufficient reserve to withstand this effect but some may become distressed and this distress can be identified and monitored.
Disadvantages of Continuous Monitoring?
A continuous CTG produces a paper recording of the baby’s heart rate and mother’s labour contractions. Whilst a continuous CTG gives a written record, it prevents women from moving during labour.
This means that women may be unable to change positions freely or use a bath to help with comfort and control during labour. It also means that some resources tend to be focused on the needs to constantly interpret the CTG and not on the needs of a woman in labour.
Does Evidence Support the Use of Continuous Electronic Fetal Monitoring in Labour?
No! In a Cochrane review, researchers found no difference between continuous and intermittent fetal heart rate monitoring, with regards to perinatal mortality, cerebral palsy, Apgar scores, and cord blood gas, admission to the NICU or low oxygen brain damage. These findings were consistent in both low risk and high risk women.
Women who received continuous monitoring were 1.7 times more likely to have a cesarean, more likely to require pain medication and more likely to have forceps or vacuum delivery when compared to the women in the intermittent auscultation group.
What Does This Mean For You in Your Labour?
Basically it means that it is yet another thing to discuss with your care provider. If continuous monitoring is standard in the hospital where you will give birth, it may hinder your ability to be mobile in labour. It may increase your chance of intervention.
If you are planning an active birth where you are free to respond to the needs of your body, where you feel deeply connected to your baby and where you trust the process of birth, then you should request intermittent fetal heart rate monitoring over continuous. (Written by Karen Wilmot)