Understanding the limitations of CTG monitoring (and indeed all fetal heart rate monitoring!) can help you to reclaim informed decision-making during your birth.

What Is a CTG and How Does It Work?

Cardiotocography (CTG) uses a machine to continuously monitor the fetal heart rate. It generally involves you lying on a bed and having two monitors on leads that are strapped to your abdomen with stretchy fabric bands. One monitor is picking up the fetal heart rate and the other is to monitor contractions based on the pressure of your uterus. A CTG can be used intermittently with the aim of assessing fetal wellbeing during the antenatal period, or it can be used continuously during labour to try and detect fetal hypoxia (lack of oxygen).

Wireless CTG Monitoring: What Is Telemetry?

Some hospitals have wireless CTG machines - known as telemetry, which means you aren’t as restricted in your movements but you do still need to stay in range of the main CTG machine. The monitors may also still lose contact (which can happed with wired monitoring too), so you may still need regular readjustment of the monitors to get a good reading. These constant readjustments can be disruptive to your labour flow and might mean you're asked to stay in a certain position or even hold the monitor to keep contact. A bonus of telemetry is that some are waterproof, so can also be used in birth pools.

What Is a Fetal Scalp Electrode (FSE)?

There is the option to have fetal electrocardiogram (fECG) monitoring via a fetal scalp electrode (FSE). An FSE is a small metal spiral that sits just under the baby’s scalp and it requires a vaginal examination to apply. It will pierce the baby’s scalp in order to be attached and the lead will then come out of the vagina and connect to the CTG machine. An FSE is used instead of the abdominal heart rate monitor. An FSE might be recommended where contact is poor via abdominal monitoring or in hospitals that use ST Analysis (STAN) in conjunction with CTG monitoring.

Does CTG Monitoring Actually Improve Birth Outcomes?

The aim of CTG monitoring is to detect fetal distress so that intervention can happen at the right time to improve outcomes. However, despite its widespread use in maternity care, research repeatedly shows that it does not significantly improve neonatal outcomes, such as cerebral palsy and neonatal death. The interpretation of CTGs is subjective and there are high rates of false positives - whereby clinicians think there’s a problem based on the fetal heart trace, which leads to potentially unnecessary interventions during birth.

CTGs have been shown to lead to higher rates of intervention, such as instrumental births and unplanned caesarean sections.

How CTG Monitoring Can Disrupt Your Labour

If you’ve ever had a CTG or are a midwife working on a labour ward, you’ll know that when a CTG is in use the focus switches from the woman to the machine. Every effort is made to ensure there is ‘good contact’ with the CTG so that a fetal heart rate trace can be interpreted. What this means is that the monitor may need to be adjusted throughout your labour if contact is lost, which can disrupt your labour flow. It will also restrict your movement or may mean that you are advised to stay in one position to get a ‘good trace’. This restriction doesn’t help your baby move through your pelvis or you manage the sensations of labour. Focusing on the CTG displaces a woman’s intuition and self-trust. CTG machines can also be very noisy, constantly beeping and many hospitals have policies recommending that a ‘Fresh Eyes’ assessment is carried out every hour with another healthcare professional. What this means is another person coming in to your birth space every hour to look at the monitor. Having these constant interruptions and distractions will not help oxytocin, that beautiful labour hormone, flow.

Who Is Advised to Have Continuous CTG Monitoring in Labour?

Generally, anyone who is considered ‘high risk’ will be advised to have continuous CTG monitoring throughout their labour. For the full list of antenatal indications and in labour indications for continuous CTG, see the NICE guidelines here. Note also that your local hospital policy may have additional recommendations surrounding fetal monitoring. NICE also advise that clinicians use their clinical judgement, taking a multidisciplinary approach and looking at the whole clinical picture to recommend a CTG if there are any other concerns in the antenatal period or in labour that could lead to fetal compromise. It’s worth noting that maternity is a very litigious area of health care, and so a CTG might be recommended out of health provider fear rather than because there is actually any indication to do one. Dr Kirsten Small has a wealth of CTG resources on her website, many of which debunk the idea that a CTG is needed in certain clinical scenarios, such as VBAC. There just isn’t good evidence that CTGs are improving outcomes or that they’re superior to intermittent auscultation (more on that below). The reality is that fetal heart rate monitoring (all types!) was introduced without any trials - it's a non-evidenced based intervention that is now ingrained in practice.

Can You Decline a CTG in Labour?

It is always your choice if you want to have a CTG or not during labour. CTGs are such a routine part of maternity care that it may just be assumed that you’ll accept one. Your doctor or midwife may advise one form of monitoring over another based on your history, but ultimately they should respect your choice. You can request to have CTG monitoring in the absence of any indications but it is worth knowing that this has been shown to lead to an increase in potentially unnecessary interventions.

What Is Intermittent Auscultation (IA)?

The other option for fetal monitoring is intermittent auscultation (IA), whereby a handheld doppler is used to listen intermittently to the fetal heart rate. Current NICE guidelines for IA advise to listen in every 15 minutes during the ‘first stage’ of labour and every 5 minutes in the ‘second stage’ of labour. It is worth noting that there is also not any good evidence to support this 15 or 5 minute protocol, but it is considered ‘best practice’. If you have managed to make it to the end of your pregnancy and retained a ‘low risk’ label, then IA is considered suitable and safe fetal monitoring for your labour. IA is the only form of fetal monitoring we offer our home birth clients.

Your Fetal Monitoring Options: Making the Right Choice for You

You can decline all fetal monitoring during labour if you wish. We don't have research comparing no fetal heart rate monitoring with fetal heart rate monitoring - it would never get passed an ethics committee. Fetal monitoring is a non-evidence based intervention that was introduced over a hundred years ago.

You may be recommended to have a CTG but choose IA instead. If you’re birthing in hospital you may choose to opt for the occasional CTG in labour instead of a continuous one. It’s worth thinking about all your options during pregnancy to see what feels right for you.

It’s your body, your birth.