Reviewing the evidence for Intermittent Auscultation

I was excited to see a new paper, setting out the evidence for intermittent auscultation in labour (Anderson, et al., 2023). It was published in a journal for US based nurse-midwives, so it relates to the context of care in that country. Let’s see how they did in terms of getting the facts right.

Is their evidence accurate?

They wrote that:

There are no trials comparing CTG use with no fetal heart rate monitoring, and no trials comparing intermittent auscultation use with no fetal heart rate monitoring in labour
Thirteen trials comparing CTG use with intermittent auscultation in labour are summarised in the 2017 Alfirevic Cochrane review
There were no differences in rates of cerebral palsy or mortality between the two approaches
Neonatal seizures were twice as common in those randomised to intermittent auscultation
Long- term follow up in one trial (the 1985 Dublin trial) showed no difference in the rate of cerebral palsy when infants with and without seizures were compared.

All this is correct, except that one of the trials in the Cochrane review compared continuous CTG use with intermittent CTG use, not intermittent auscultation, and another compared liberal CTG use with restricted CTG use. So strictly speaking there were eleven trials comparing CTG use with intermittent auscultation – but that doesn’t alter the overall message here.

They went on to correctly describe evidence about the problem of variability in interpretation of CTG recordings and the absence of evidence to support the use of fetal blood sampling, fetal oximetry, and fetal ST segment analysis. They also correctly summarised research showing the lack of correlation between MRI evidence of brain injury and abnormal fetal heart rate patterns. Nice work!

Did they get anything wrong?

Like many other authors writing about fetal heart rate monitoring in labour, the first sentence of their paper has the potential to misdirect. They wrote:

Intermittent auscultation is an effective yet under-utilized means of assessing fetal well-being in birthing individuals who are at low risk.
p. 173

This sentence, and others similar to it, generate the impression that intermittent auscultation is not also an effective yet under-utilised means of assessing fetal wellbeing in women who are at high risk. Yet research makes it clear this is the case. If the phrase “who are at low risk” were deleted from their sentence, it would be more accurate. Somehow this well established fact has been deemed to be controversial. I suspect many authors are reluctant to come right out and say it in case peer reviewers reject their paper.

The authors also provide a table titled “suggested screening for appropriateness of intermittent auscultation” listing eight conditions with a higher risk for poor perinatal outcomes (with no source for this cited). In a similar way to the sentence above, this creates the impression intermittent auscultation is inappropriate for women with one of these conditions. This makes it far less likely it will be even offered as an option. It would be better to label this list as “conditions with a higher risk for poor perinatal outcomes”. That is factually accurate, and doesn’t suggest the presence of risk should direct the decision about whether or not to offer a certain approach to fetal heart rate monitoring.

Moving towards evidence-based decision-supporting conversations about fetal heart rate monitoring

What do I think we should be writing about in maternity care in relation to fetal heart monitoring? I’d like to see authors presenting both CTG monitoring and intermittent auscultation as valid choices, for all women, regardless of risk factors.

What should be happening in clinical practice? All women who plan to labour should have their maternity professional explain what CTG monitoring and intermittent auscultation are, and what the evidence actually says (and doesn’t say) about them. I’d like to see every woman be given an accurate estimate of her personal risks for a poor perinatal outcome, followed by an acknowledgement that while we use CTG monitoring in an attempt to reduce the chance of that happening, we have no good evidence to prove it is effective. I’d like to see honest discussions about the risks of CTG use for women and babies, including when fetal spiral electrodes are used. And I’d like to see support for women to own the decision making here (if they want to, and most do,) and for women to receive respectful care honouring that decision once it has been made.

Now is probably a good time to remind you, that if you don’t know the evidence, you can’t have an evidence-based conversation. I have courses specifically designed to fix that issue, whether you are a registered maternity professional or birth worker not required to hold professional registration. Hopefully early in 2024 I’ll have one for women who are , or are planning to be, pregnant as well.

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References

Alfirevic, Z., Devane, D., Gyte, G. M. L., & Cuthbert, A. (2017, Feb 03). Continuous cardiotocography (CTG) as a form of electronic fetal monitoring (EFM) for fetal assessment during labour. Cochrane Database of Systematic Reviews, 2(CD006066), 1-137. https://doi.org/10.1002/14651858.CD006066.pub3

Anderson, K., Salera-Vieira, J., & Howard, E. (2023, Jul-Sep 01). The evidence for intermittent auscultation. Journal of Perinatal & Neonatal Nursing, 37(3), 173-177. https://doi.org/10.1097/JPN.0000000000000754