Electronic fetal heart rate monitoring: new research approaches are needed
The BMJ must be commended for this timely head-to-head debate, where doctors supporting electronic fetal heart monitoring seem to ‘cherry-pick’ evidence, and the principal investigator of many great obstetric trials including INFANT (a UK RCT involving 47 062 women) (1) explains the uncertainties. Cochrane (2), FIGO (3) and NICE (4) have all admitted there is no evidence that human or computerised interpretation of cardiotocographs (CTG) reduces intrapartum stillbirth and cerebral palsy, but does cause maternal harm. INFANT showed that adding intelligent decision support to costly and demanding CTG technology did not improve clinical outcomes for mothers or babies (1). A previous commentator facing the limits of this monitoring in the prevention of neonatal metabolic academia rebuffed the repetitive call for yet more “improved scientific pattern recognition of fetal heart rate decelerations and use of adjunctive test”, quoting the Institute of Medicine: “Trying harder will not work. Changing systems of care will.” (5)
We propose two new approaches to making care of fetal and neonatal hypoxia simple and cheap rather than complicated and costly with computerized CTG:
First, the assessment of mobile resuscitation devices designed specifically to facilitate newborn resuscitation at the bedside with an intact cord, as separating the newborn from its placental transfusion iatrogenically interferes with ‘auto-resuscitation’.(6) Indeed, timely management of complications is the cornerstone for recovery.
Second, labour use of carbon monoxide (CO) breath analyzers, a simple, cheap, fast and non-invasive technology, to identify the most frequent conditions responsible for hypoxia and metabolic academia: Carboxyhemoglobin (HbCO) due to smoking or underestimated environmental causes (heating systems, motor vehicles etc.). When CO is inspired, fetal HbCO increases more slowly than maternal concentration but can attain twice as high levels and prolonged, low level exposures can result in extremely high tissue concentrations. Tissue hypoxia and direct action on haem-containing proteins (myoglobin,cytochromes) are key mechanisms responsible for CO’s fetal toxicity. Additionally, pulse oximetry is inadequate to detect carbon monoxide poisoning because carboxyhemoglobin can be misinterpreted as oxyhemoglobin.
The over-longstanding reliance on CTG highlights the effect of a rigid mindset but might be related to vested interests from equipment manufacturers and plaintiff lawyers and experts who find lucrative medico-legal practices.
1 The INFANT Collaborative Group. Computerised interpretation of fetal heart rate during labour (INFANT): a randomised controlled trial. Lancet 2017;389:1719-1729
2 Alfirevic Z, Devane D, Gyte GML, Cuthbert A. Continuous cardiotocography (CTG) as a form of electronic fetal monitoring (EFM) for fetal assessment during labour. Cochrane Database of Systematic Reviews 2017, Issue 2. Art. No.: CD006066. DOI:10.1002/14651858.CD006066.pub3
3 Ayres-de-Campos D, Spong CY, Chandraharan E et al. FIGO consensus guidelines on intrapartum fetal monitoring: Cardiotocography. Int J Gynecol & Obstet 2015;131:13–24.
4 NICE CG190. Intrapartum care for healthy women and babies. 2014. https://www.nice.org.uk/guidance/cg190
5 Clark SL, Hamilton EF, Garite TJ et al. The limits of electronic fetal heart rate monitoring in the prevention of neonatal metabolic acidemia. Am J Obstet Gynecol. 2016;163.e1–163.e6 and Reply. Am J Obstet Gynecol 2017;216:93
6 Weeks AD, Watt P, Hutchon DJR, Yoxall CW, Gallagher A, Bewley S, Odd D, Burleigh A, Fisher T, Heuchan AM, Duley L. Innovation in immediate neonatal care: development of the Bedside Assessment, Stabilisation and Initial Cardiorespiratory Support (BASICS) Trolley BMJ Innov 2015;1:53–58.
Competing interests: SB chaired NICE 2014 Intrapartum Care Guideline Development Group CG190. AB has no link to declare.