Intermittent auscultation outperforms more modern methods at reducing cesarean sections

University of WarwickApr 7 2021

Intermittent auscultation, in which the baby’s heartbeat is monitored using a sonic aid or Doppler probe, outperforms more modern methods at reducing the number of emergency caesarean sections in labor, according to a new study led by researchers from the University of Warwick.

Although several alternative methods of monitoring the welfare of the baby during birth have been developed in recent decades, their research has found that none of these has made an impact on reducing the number of emergency caesareans carried out with no benefit to mother or baby.

The research, published today (6 April) in the Canadian Medical Association Journal, suggests that these newer methods are not helping clinicians to distinguish whether a mother requires an emergency caesarean any better than the older, more established method of intermittent auscultation of the baby’s heartbeat.

Standard practice in maternity units is that every woman in labor is offered monitoring to ensure her baby is safe. When a clinician detects signs that labor is not going well then they will stop labor and expedite delivery with an emergency caesarean section.

Intermittent auscultation was introduced more than forty years ago to help clinicians detect when a baby is not coping with labor. Today, there are a number of alternatives designed to provide them with more information about the baby, known as fetal surveillance, including using echocardiograms, blood tests and AI modelling.

Although several clinical trials have been performed on these methods before, this is the first time that all these methods have been compared against each other. For this study, the research team conducted a systematic review and a novel network meta-analysis of 33 previous randomized trials on the topic, that involved a total of 118,000 women worldwide, one of the largest and most comprehensive studies of its kind. They found that all surveillance methods yielded similar outcomes for the babies, but only intermittent auscultation reduced caesarean sections without any additional risk to babies’ safety. The researchers estimate that use of intermittent auscultation led to an average 30% reduction in emergency caesareans compared to other methods (ranging from 20% to 40% depending upon the comparison method).

Sadly, all the contributions we’ve done in this field for the last forty years are not yielding a significant benefit to make childbirth safer. The outcome of any labor should be a healthy mother going home with a healthy baby. We aimed to find the method of fetal surveillance that offers the best diagnostic accuracy to help identify those babies at risk without increasing the number of emergency caesarean sections. Specifically those sections that are not yielding a clear benefit to improve babies’ wellbeing. Only intermittent auscultation achieved this objective in our study.”

Dr Bassel Al Wattar, Lead Author and NIHR Academic Clinical Lecturer, Warwick Medical School

A caesarean section would normally be performed either by maternal request, as per recent NICE guidelines, or if clinicians feel there is imminent danger to the mother or baby’s health. An emergency caesarean performed for an incorrectly suspected fetal compromise could yield an unnecessary risk to the mother, prolong her stay in hospital and increase the risk of complications in future pregnancies.

We suspect that the problem with some of these monitoring methods is that they’re sending fake signals that the baby is compromised when it isn’t, and therefore a caesarean section is being performed to no clear benefit. It is important to note that our findings do not suggest that new monitoring methods are harmful or increasing emergency caesarean sections, but they are simply not helping to reduce them or improve childbirth safety compared to older, cheaper and widely accessible technology.

This is a very relevant public health priority, however the research performed to date is not yielding a significant benefit to address this problem. It can only be addressed by performing very large clinical trials and evaluating all available interventions, and at the same time investing in technology innovation to give us better monitoring tools. It is a sad truth that even with the use of highly sophisticated equipment, there are babies born with signs of oxygen deprivation. Therefore, it is imperative that we invest in ways of monitoring labor that provides a significant benefit over traditional methods.’’

Siobhan Quenby, Professor of Obstetrics at the University of Warwick, Honorary Consultant at University Hospital Coventry and Warwickshire NHS Trust