Intrapartum fetal monitoring is going through a period of intense scrutiny in the UK. Midwives are on the front line of cardiotocography (CTG) interpretation and intermittent auscultation (IA) of fetal heart rate (FHR) during labour. A consultation on a ‘draft addendum’ for exceptional review of the National Institute for Health and Care Excellence (NICE, 2014) guidelines regarding intrapartum fetal monitoring closed on 25 November 2016. One of the questions posed for consultation was: for how long and when should the fetal heart be auscultated? For example, one minute during or immediately after a contraction or between contractions? It was important for midwives to express their views on this question—as individuals or through their representatives—in the registered stakeholder institutions, especially because British obstetricians in general have little training, experience or interest in IA, and do not practise it. Moreover, there is more to discuss concerning IA with the availability of new handheld Doppler FHR monitors, which provide numerical readouts as well as ‘FHR trace display’ during the auscultation period (e.g. the Huntleigh Sonicaid SR2 digital Doppler). These intermittently-recorded FHR traces could be replayed during labour and downloaded onto computers to be archived in a patient's electronic record. Further amendments to guidelines could be an opportunity to comment on the place of additional functionality in midwifery practice of IA, especially regarding accountability and medico-legal implications. Some maternity units in the UK have already purchased these more advanced Doppler monitors because they are only slightly more expensive but provide an extra dimension of functionality. Moreover, the older Doppler monitors may be eventually phased out. Most maternity units use the new monitors to simply read numerical displays of FHR across 1 minute (after contractions), which are then documented in clinical notes without viewing or archiving of the intermittent FHR traces. This article critically analyses the possible role of the latest Doppler monitors in IA, especially in the context of current guidelines and any future addenda.
Pros and cons of FHR trace display during IA
The hand-held Doppler monitors have been improved to become very robust, reliable, and cost-efficient. Further innovations could open new possibilities for intrapartum fetal monitoring in future. It would be tempting to assume that the FHR trace display on handheld Doppler monitors must have an unfettered advantage, since it allows the detection of FHR baseline variability, detection of decelerations, and archiving of traces for retrospective review. However, the main advantage of IA is its simplicity and practicality in midwife-led units, home births and rural settings. Moreover, trace recording and archiving is likely to exponentially increase (rather than decrease) medical litigation as happened with CTG with debatable benefits. Errors can be made even on proper CTG record when assessing FHR baseline variability, and it would be suboptimal to try and assess it on the small display screen of the handheld Doppler monitor. Moreover, at least in low-risk cases, there is no benefit of CTG over IA (NICE, 2014) and midwives need not be required to comment on baseline variability (a domain of CTG) during IA (Sholapurkar, 2015a).
The FHR trace display on handheld monitors would be expected to show FHR decelerations very reliably, but its major disadvantage is that the uterine activity is not recorded(although a toggle to manually record a contraction could be added). The FHR decelerations therefore cannot be related to the timing of contractions, especially in retrospect. Hence, a clear understanding of which FHR decelerations need to be acted upon becomes even more important. The British guidelines (Royal College of Obstetricians and Gynaecologists (RCOG), 2001; NICE, 2007; NICE, 2014) recommended auscultation of FHR for 60 seconds immediately following a uterine contraction, which is clearly intended to detect ‘late’ decelerations and/or an abnormal FHR baseline. It has been reported that strict adherence to these guidelines may be missing many late decelerations because their nadir is commonly reached towards the end of contraction; auscultation after the contraction may be mistakenly interpreted as an accelerative pattern (Sholapurkar, 2015a). It would be possible to auscultate before, during, and after the contraction with a handheld Doppler device, provided any FHR decelerations limited to contractions are ignored (Sholapurkar, 2015a). In late 2015, the International Federation of Gynaecologists and Obstetricians (FIGO) issued its guideline for IA (Lewis and Downe, 2015) for the first time. It did recommend more extended auscultation during and after uterine contraction, but advised CTG to be commenced if any decelerations are suspected, even if limited to the contractions. Some experts hold an opinion that decelerations confined to contractions could be pathological, but there is little evidence for this view (Sholapurkar, 2015a).
Let us suppose that the FIGO (Lewis and Downe, 2015) guidelines on IA are followed and FHR decelerations are heard during contractions, leading to commencement of CTG. According to the FIGO CTG guidelines, these FHR decelerations during contractions will be called ‘variable decelerations’ and considered pathological only if their duration exceeds 3 minutes (Ayres-de-Campos et al, 2015). However, contractions almost never repeatedly last for more than 3 minutes, even when the uterus is overstimulated. It seems obvious that decelerations limited to contractions would not exceed 3 minutes repeatedly, hence would not be pathological. Decelerations of more than 3–minute duration that start with contractions would always extend into the 1–minute period after the end of contraction and hence would be detected by the current IA if properly performed. Thus, the FIGO–CTG guideline nullifies this FIGO–IA guideline recommendation. Even though the arbitrary 3–minute criterion by FIGO (Ayres-de-Campos et al, 2015) seems wrong, there are sound pathophysiological hypotheses as well as long-standing British practice and experience which supports the notion of the benign nature of decelerations coinciding with contractions (Sholapurkar, 2015b). Thus, if FIGO guidelines (Lewis and Downe, 2015) on IA are followed, then many low-risk labours would be unnecessarily switched over to CTG or transferred to obstetric units, disempowering midwives and patients (Sholapurkar, 2015a). This would be against the desired goal of NICE and Royal College of Midwives (RCM) to conduct up to 40% of all labours in midwifery-led low-intervention settings or homes (Roberts, 2014). Moreover, evidence from randomised controlled trials shows that the CTG (as interpreted) has no benefit over IA, despite increased operative intervention (NICE, 2014).
The advantage of the FHR trace display on Doppler monitors is that it would be relatively easy to ascertain the FHR baseline, which would assist in detection of late decelerations after contractions. But the presence of FHR decelerations on the trace display (without tocography trace) during extended auscultation, especially during contractions, would generate great anxiety for midwives in these unsettling times. Bearing this in mind, the NICE/RCM should append guidance on IA to recommend that midwives avoid using the FHR trace display function at present, or that the FHR traces should be viewed only after restricting the auscultation from the end of one contraction to the beginning of the next. Alternatively, if auscultation is performed during contractions as well, then only the decelerations repeatedly extending or occurring beyond the palpable uterine contractions should prompt a switch to CTG. Until such new addenda, it would be problematic to incorporate the trace displays. For the time being, because of these limitations, these traces are best not archived for retrospective accountability or for medico–legal purposes in the context of IA being a low-tech monitoring method applied to low-risk labours.
Conclusions
Midwives should take an active and leading role in formulating the guidelines of IA. The improved handheld Doppler monitors with ‘FHR trace display’ are a welcome and exciting development. This functionality could be useful when there is doubt about baseline variability or late decelerations. It may evolve into a bridging technique between IA and CTG but it is hard to prove the benefits. The NICE/RCM should recommend that only ‘late’ FHR decelerations or abnormal FHR baseline should require switch over to CTG, as has been the previous long-standing sound British practice.