Updated: October 2022
Listening to the baby’s heart rate during labour is considered to be an important aspect of routine midwifery care. There are two methods of listening—intermittent auscultation (IA) and continuous electronic monitoring (CEFM) via a cardiotocograph machine (CTG).
This post is not going to discuss the technical ‘how to’ or ‘what to look for’ when listening to baby. Instead, this is more of a reflection on the evidence and practice of listening and how it might be done in a more woman-centred way.
Intermittent Auscultation (IA)
In the 1800s physicians and midwives began using fetal stethoscopes to listen to babies’ hearts through women’s abdomens. Initially, this was only carried to assess if the baby was alive during complicated births. It was not routine. You can read more about the history of auscultating the fetal heart rate in an article by Maude, Lawson and Foureur (2010).
The Pinard (pictured) was designed by Adolphe Pinard a French Obstetrician and founder member of the French Eugenics Society. The electronic hand-held Doppler is also named after the man who invented it – Christian Doppler.
With a Pinard you can hear the baby’s heart sounds directly. That’s why it is important for midwives to be skilled in its use. A Pinard should be used before starting any electronic monitoring to ensure the heart rate is being accurately recorded. The Doppler uses short pulses of ultrasound waves to detect movement and turns those movements into sound. It can create a ‘fetal heart rate’ sound out placental or maternal blood vessels. At CTG can do the same.
IA is recommended in clinical guidelines for all ‘low risk’ women during labour. The recommended frequency of IA is usually every 15-30 minutes during the ‘first stage’ of labour and after every contraction (or more often if contractions are longer than 5 mins apart) during the ‘second stage’. Of course, this raises questions about the concept of ‘stages’ of labour, but that’s a whole other blog post. However, there is NO research to date examining whether the practice of fetal heart rate auscultation improves outcomes, or the optimal frequency of auscultation. If you follow the citations in guidelines, they cite each other and occasionally you find a study by Kaunitz et al. 1984. This study did not specifically assess IA. In the researcher’s words: “We investigated perinatal and maternal deaths occurring among women who were members of a religious group in Indiana; these women received no prenatal care and gave birth at home without trained attendants.” There was a significantly higher rate of perinatal and maternal death in the religious group, leading the researchers to conclude that: “Women who avoid obstetric care have a greatly increased risk of perinatal and maternal death.” However, there were more pre-term and growth restricted babies in the religious group. And, this study did not indicate that fetal heart rate monitoring was the factor causing the different outcomes.
I have been unable to find research specifically exploring women’s experiences of IA (surprise, surprise). If you find some, let me know.
There may be theoretical and experiential evidence to support the practice of IA, and to be honest, I think it is here to stay. There will never be a good quality RCT to assess the effectiveness of IA because it would be unethical to allocate a group of women to labour without IA. This intervention is a firmly embedded cultural norm that women usually expect from their midwives during labour. However, we need to consider how this intervention is carried out.
Some concerns about prescriptive IA
While hearing a ‘normal’ fetal heart rate can be reassuring for both midwife and mother, there are a number of issues associated with the IA:
- The frequency of IA has been plucked out of the air and increases without evidence (the excessive IA during pushing is relatively new).
- IA involves doing something to the birthing woman – anything you do may interfere with the physiology of birth (ie. stimulate the neocortex and disrupt instinct).
- The woman may have to move from an instinctively perfect position so that you can ‘get in’ to listen.
- IA can create anxiety and concern if the heart rate is difficult to find or not ‘normal’. In the pushing phase of labour, 75% of babies will have an ‘abnormal’ heart rate due to normal physiological processes such as head/neck compression (Sheiner et al. 2001). Abnormal patterns in the ‘second stage’ are only significant if there were abnormal patterns in the ‘first stage‘ of labour (Sheiner et al. 2001; Loghis et al. 1997; Wu, Chen & Wang 1996).
Suggestions for IA
Before labour discuss IA with the woman:
- Reinforce that she is the expert in her baby’s well-being. Encourage her to connect with her baby and trust her instincts regarding their health in pregnancy, labour and beyond.
- Find out how often would she like you to listen to her baby, and if she would prefer you to use a Doppler or a Pinard? Explain that she can change her mind at any time during labour about when and how you listen to her baby.
- Explain that while she is pushing her baby out there will be some changes to the heart rate pattern and that this is normal.
- Explain how you plan to listen to her baby (see below) and check that she is happy with this approach.
- Fit the timing of IA around the woman’s preferences and what is going on rather than set time intervals.
- Avoid stimulating her neocortex by asking, ‘can I listen in?’ Instead, gently move towards her with the Doppler/Pinard. Have a prior agreement that she can move away or push your hand away if she doesn’t want you to listen.
- If the heart rate has been normal throughout the labour, and there are no risk factors (eg. coached pushing) – there is no need to increase IA during the pushing phase.
- When the baby’s head is crowning, it can be incredibly difficult and uncomfortable to locate the fetal heart sounds because of the position of the baby in the pelvis. Instead, observe the colour of the baby’s scalp to assess oxygenation—a nice pink scalp = a well-oxygenated baby.
I am aware that my suggestions may be difficult for midwives caring for women they don’t know in a hospital setting. As usual, I am being idealistic rather than prescriptive.
Continuous Electronic Fetal Monitoring (CEFM)
Clinical guidelines recommend CEFM for ‘high risk’ women and warn against it for ‘low risk’ women. Despite recommendations, CEFM is a cultural norm in many birth settings for all women. CEFM is yet another intervention that was introduced without evidence to support its effectiveness at improving outcomes.
Most clinicians working in hospital settings will have regular training in interpreting cardiotocograph (CTG) traces. In my time as a midwife, I have completed many hours of CTG training and taught CTG assessment to midwives and students. I actually enjoyed the systematic nature of working through a trace. So, I find it disappointing to acknowledge that the apparently ‘concrete’ interpretations of the wiggly lines on the paper are not so concrete.
A Cochrane Review (Alfirevic et al. 2017) compared CTG with IA during labour for low-risk, medium-risk and high-risk women. The studies included ranged from the 1970s to 2016 and had categorised risk in contradictory ways. For example, some categorised induction as ‘low risk’. The review concluded: “CTG during labour is associated with reduced rates of neonatal seizures, but no clear differences in cerebral palsy, infant mortality or other standard measures of neonatal wellbeing. However, continuous CTG was associated with an increase in caesarean sections and instrumental vaginal births. The challenge is how best to convey these results to women to enable them to make an informed decision without compromising the normality of labour.” So, the only improved outcome for women with CEFM was a reduction in the overall neonatal seizure rate from 30 in 10,000 (IA) to 15 in 10,000 (CTG). Interesting, this difference was not significant for ‘high risk’ women and was most significant for ‘low risk’ women. Neonatal seizures are a short-term outcome, and there were no significant long-term outcomes eg. cerebral palsy.
A more recent systematic review and network meta-analysis (Bassel et. al 2021) looked at IA vs CTGs and the associated new technologies (fetal blood sampling, lactate assessment, etc.). It did not find a difference in newborn outcomes (acidemia, SCN admissions, low Apgar scores or perinatal death). The authors concluded: “Compared with other types of fetal surveillance, intermittent auscultation seems to reduce emergency cesarean deliveries in labour without increasing adverse neonatal and maternal out comes. New fetal surveillance methods did not improve neonatal outcomes or reduce unnecessary maternal interventions.”
A large retrospective study (Heelan-Fancher et al. 2019) explored the impact of CEFM on women with low-risk pregnancies in two States in the US. CEFM increased the c-section rate and the instrumental birth rate in both States. In one State it reduced the risk of neonatal mortality for early term babies (37-38+6 weeks). The authors conclude: “The study results do not support universal use of CEFM in pregnancies that are low-risk and at term.”
Small et al. (2020) conducted a literature review or studies looking at CEFM for ‘women at risk‘. Of the 26 studies included, 21 were at ‘critical or serious risk of bias’, and therefore excluded from the review. In the 5 studies reviewed, there was no difference in stillbirth or neonatal death. They found that CEFM during pre-term labour was associated with a higher incidence of cerebral palsy. The authors state that “Research evidence failed to demonstrate perinatal benefits from intrapartum cardiotocograph monitoring for women at risk for poor perinatal outcome.”
So, there you go… confusing and conflicting research findings regarding CFM and newborn outcomes. Yet, very clear findings regarding the increase of c-section and instrumental birth for women with CFM.
Research looking at women’s experience of CFM is limited. A systematic review (Crawford et al. 2017) of 5 studies found that CFM “was reported to have high levels of participant satisfaction and was preferred by women to intermittent cardiotocography.” Which is not surprising if women think it improves outcomes for their baby (and were they told of the increased risk of surgical birth?). The authors conclude: “This review suggests that continuous fetal monitoring is accepted by women. However, it has also highlighted both the paucity and heterogeneity of current studies and suggests that further research should be conducted into women’s experiences of continuous fetal monitoring before such devices can be used clinically.”
An ethnographic (qualitative) study explored clinicians’ experiences of centralised CEFM. The findings are published in two journal articles (Small et al. 2021; Small et al. 2022). I’m sure there will be no surprises in the findings for anyone working in settings with centralised CEFM:
“The introduction of the central monitoring system was associated with clinical decision making without complete clinical information. Midwives’ work was disrupted. Higher levels of anxiety were described for midwives and birthing women. Midwives reported higher rates of intervention in response to the visibility of the cardiotocograph at the central monitoring station. Midwives described a shift in focus away from the birthing woman towards documenting in the central monitoring system.” (Small et al. 2022)
“Midwives described a disruptive social event they named being K2ed. Clinicians responded to perceived cardiotocograph abnormalities by entering the birth room despite the midwife not having requested assistance. Being K2ed disrupted midwives’ clinical work and generated anxiety. Clinical communication was undermined, and midwives altered their clinical practice. Midwives performed additional documentation work to attempt to avoid being K2ed.” (Small et al. 2021)
The researchers raise concerns about centralised CEFM and conclude: “This is the first report of an unintended consequence relating to central fetal monitoring, demonstrating how central fetal monitoring technology potentially undermines safety by impacting on clinical and relational processes and outcomes in maternity care.” (Small et al. 2021)
Like IA, CEFM, particularly for women with ‘high risk’ pregnancies, is here to stay. There is too much invested financially and culturally to withdraw this questionable and widespread intervention. In addition, it is important to assess the impact of any intervention on mother and baby. Personally, I would be very concerned about carrying out an induction of labour without CEFM of the baby. The risks are too high and being able to see the baby’s response provides a sense of control and safety (a rite of protection) regardless of evidence. However, it could be argued that putting a CTG on a ‘low risk’ woman having a spontaneous labour creates risk and danger.
Suggestions for CEFM
- Discuss the evidence with women and provide adequate information about the benefits and risks to gain consent (or for her to decline).
- Discuss the process ie. what it involves (eg. that other staff may assess the trace), and options (eg. does she want the monitor turned away from her? the volume turned down? an explanation of the trace or just an overview ie. ‘it’s good’), what will happen when a variation or abnormality is identified.
- Fit the monitor around the woman. Even CTG monitors with straps can be used while the woman is mobile (obviously dependent on epidural).
- Make sure you get a decent trace. There is no point in having a CTG on if it is not effectively recording a trace.
It would be great if you could leave your tips for woman-centred CEFM in the comments.
- Reclaiming Childbirth as a Rite of Passage (Reed 2021)
- Intelligent Structured Intermittent Auscultation (ISIA): evaluation of a decision-making framework for fetal heart monitoring of low-risk women (Maude et al. 2014)
- Putting intelligent structured intermittent auscultation (ISIA) into practice (Maude et al. 2016)
- Intermittent auscultation (IA) of fetal heart rate in labour for fetal well-being (Maude et al. 2017)