Electronic fetal monitoring in labour can be achieved via two main methods – continuous and intermittent monitoring (also known as intermittent auscultation).

Continuous monitoring is achieved by using an ultrasound wave and pressure sensors to monitor baby’s heart rate, the mothers heart rate and contractions. This is typically called cardiotocography (CTG) tracing. A CTG is usually two small monitors secured in place by soft straps around the abdomen. CTG devices can be wired or Bluetooth - depending on the healthcare facility.

As this method is often used in high-risk labours, the CTG trace displays the fetal heart rate in great detail - including any accelerations, decelerations, high or low heartrates and baseline variability. It will also record uterine activity including tightening’s/contractions.  

This helps healthcare providers to monitor the progression of labour and how the baby responds to these changes.

Intermittent monitoring

Intermittent auscultation involves healthcare professionals listening to the fetal heart rate for short periods at regular intervals. This is achieved using a small hand-held, waterproof device known as a doppler. In early labour, this monitoring will likely be infrequent - however as labour progresses, the time between intervals will shorten.

In the second stage of labour (and during active pushing) the provider will likely be listening to the fetal heart rate with every contraction.

Benefits:

• Freedom to move around the room without interference
• Less perceived intervention
• Water resistant, can be used in shower and/or bath
• Can labour in any position – upright, all-fours, standing and away from the bed.
• Research suggests it can reduce the chances of further medical intervention that may/may not be necessary.

Negatives

• Has potential to cause more interruptions than a continuous monitor which is secured in place throughout labour (provided there are minimal connectivity issues with the continuous method in comparison)
• Does not provide a full picture of fetal response and behaviour in labour (however, it is argued this picture is not necessary, in theory, for healthy, low-risk labour and deliveries)

Continuous monitoring

Continuous fetal monitoring was introduced in the late 1970’s. There is still lower quality evidence regarding its introduction as healthcare was (and still is!) a rapidly changing environment. The rates of stillbirth were already decreasing when CFM was introduced, which makes the evidence difficult to interpret in its entirety.

In modern society, continuous monitoring in labour has been estimated to increase chances of caesarean by 24% in comparison to an estimated 11% with intermittent monitoring.

However, the necessity of these interventions cannot be comprehensively known as the alternative (no intervention, despite suspicions of fetal compromise) has not been studied.

Benefits

• Continuous evidence of baby wellbeing, response and adaptability to the changes of labour
• Increased ability to predict and respond to potential issues based on a larger scale picture
• Ability to determine if interventions (particularly induction of labour, pain relief and other medications) have negative impacts and how best to respond
• Reassurance to mother and healthcare providers

Negative impacts

• Increased and perceived increased intervention
• Connectivity issues, leading to the need for improvement techniques (limiting mother’s movement, applying a ‘clip’ onto baby’s head called a fetal scalp electrode)
• Alarm sounds when loss of contact, disruption of birthing ambiance
• Less freedom to move without impacting trace connectivity
• If not telemetry monitoring, then mother is limited to the distance of the cord from the CTG

Fetal Scalp Electrode (FSE) monitoring

A fetal scalp electrode or ‘clip’ that can be fastened to the superficial skin layer of a baby’s head in labour as needed. It is not routinely offered, but ideally only as a ‘last resort’ method, following attempts to monitor the baby externally have proved difficult.

Benefits:

• Assurance heartbeat heard is baby and not mother – crucial in circumstances where baby wellbeing is in question
• Comfortable for mother, not external monitoring requiring straps that can dislodge
• Can be used in all labouring positions
• Allows for better personal space overall and requires less interruptions

Negatives:

• Reduces distance mobilisation in labour if not telemetry monitoring
• Invasive procedure initially as the FSE requires a vaginal examination to attach to baby
• Infection risk associated with any vaginal examination
• Superficial skin and soft tissue damage to the baby
• Infection risk with associated above mentioned skin breakage
• May not be able to successfully attach FSE in correct location leading to further monitoring issues

Do you need fetal monitoring in labour?

When it comes to fetal monitoring, it is important you are fully informed to make an educated decision. If continuous fetal monitoring is recommended to you, there is likely an appropriate reason, but request the rationale as to why! If you are aiming for a more natural experience of labour, ask your healthcare provider to advocate for you. This will reassure you that their decisions to monitor your baby in labour are in your baby’s best interest (and yours!).

Written by Keryn Thompson RM & IBCLC (L-301766)

References

Afors, K. and Chandraharan, E., 2011. Use of Continuous Electronic Fetal Monitoring in a Preterm Fetus: Clinical Dilemmas and Recommendations for Practice. Journal of Pregnancy, 2011, pp.1-7.

Alfirevic, Z., Gyte, G., Cuthbert, A. and Devane, D., 2017. Continuous cardiotocography (CTG) as a form of electronic fetal monitoring (EFM) for fetal assessment during labour. Cochrane Database of Systematic Reviews, 2019(5).

Bhogal, K. and Reinhard, J., 2010. Maternal and fetal heart rate confusion during labour. British Journal of Midwifery, 18(7), pp.424-428.

Blix, E., Maude, R., Hals, E., Kisa, S., Karlsen, E., Nohr, E., de Jonge, A., Lindgren, H., Downe, S., Reinar, L., Foureur, M., Pay, A. and Kaasen, A., 2019. Intermittent auscultation fetal monitoring during labour: A systematic scoping review to identify methods, effects, and accuracy. PLOS ONE, 14(7), p.e0219573.

Buttigieg, G., 2015. The shifting sands of medico-legal intra-partum Ctg (I-P Ctg) monitoring. Medico-Legal Journal, 84(1), pp.42-45.

East, C., Begg, L., Colditz, P. and Lau, R., 2014. Fetal pulse oximetry for fetal assessment in labour. Cochrane Database of Systematic Reviews,.

Pinas, A. and Chandraharan, E., 2016. Continuous cardiotocography during labour: Analysis, classification and management. Best Practice & Research Clinical Obstetrics & Gynaecology, 30, pp.33-47.

Smith, V., Begley, C., Clarke, M. and Devane, D., 2012. Professionals’ views of fetal monitoring during labour: a systematic review and thematic analysis. BMC Pregnancy and Childbirth, 12(1).

Vayssière, C., Tsatsaris, V., Pirrello, O., Cristini, C., Arnaud, C. and Goffinet, F., 2009. Inter-observer agreement in clinical decision-making for abnormal cardiotocogram (CTG) during labour: a comparison between CTG and CTG plus STAN. BJOG: An International Journal of Obstetrics & Gynaecology, 116(8), pp.1081-1088.

Velimala Ratna, K., Indiramani, I., Kousalya, C. and A, A., 2015. A COMPARATIVE STUDY OF PERINATAL OUTCOME IN LOW RISK PREGNANCIES WITH CTG MONITORING AND INTERMITTENT AUSCULTATION. Journal of Evolution of Medical and Dental Sciences, 4(105), pp.17038-17042.