Intermittent Auscultation in Labor: Could It Be Missing Many Pathological (Late) Fetal Heart Rate Decelerations? Analytical Review and Rationale for Improvement Supported by Clinical Cases

Intermittent auscultation (surveillance) of fetal heart rate in labor: a progressive evidence-backed approach with aim to improve methodology, reliability and safety

Intermittent auscultation (IA) of fetal heart has become acceptable in low risk labors even in the developed countries. However, the instances of birth asphyxia occur despite adhering to the guidelines. Such outcomes need not be the inherent limitations of IA, but improvements in the IA regime are highly desirable. The systematic analyses of available studies have been unhelpful to ascertain an optimal regime or suggest improvements. This analytical review uses detailed modeling and reasoning to examine/propose safe and effective regime. It counters a misconception that the Doppler-device is not superior to Pinard stethoscope in usability, accuracy and thereby decision making. Importantly, the Doppler-device should not be used to actually count the fetal heart tones (like a Pinard stethoscope) as insisted by many guidelines. The review demonstrates that counting to 120-160 over a minute is arduous, superfluous and fraught with fallacies and risks. Observation of the digital read-out of the fetal heart rate (FHR) and its trend during the auscultation duration is far more informative. IA should focus on the two FHR parameters namely the baseline and late decelerations. Detection of additional FHR changes like overshoots, cycling or accelerations do not add value. Doppler-device FHR readouts over a steady pattern (commonly just before the contraction) best represent the baseline. FHR observation (IA) should commence in the later part of the contraction and continue till the beginning of next contraction and need not arbitrarily end at 1 min (a legacy of preoccupation with actual counting). Heightened awareness is required to detect late decelerations at the end of contractions. It would suffice to perform IA over a couple of contractions every 20-30 min during the first stage of labor. This improved methodology would avoid mistakes and improve the detection of FHR abnormalities to enhance patient safety in future practice guidelines.

Intermittent auscultation fetal monitoring during labour: A systematic scoping review to identify methods, effects, and accuracy

Background

Intermittent auscultation (IA) is the technique of listening to and counting the fetal heart rate (FHR) for short periods during active labour and continuous cardiotocography (CTC) implies FHR monitoring for longer periods. Although the evidence suggests that IA is the best way to monitor healthy women at low risk of complications, there is no scientific evidence for the ideal device, timing, frequency and duration for IA. We aimed to give an overview of the field, identify and describe methods and practices for performing IA, map the evidence and accuracy for different methods of IA, and identify research gaps.

Methods

We conducted a systematic scoping review following the Joanna Briggs methodology. Medline, EMBASE, Cinahl, Maternity & Infant Care, Cochrane Library, SveMed+, Web of Science, Scopus, Lilacs and African Journals Online were searched for publications up to January 2019. We did hand searches in relevant articles and databases. Studies from all countries, international guidelines and national guidelines from Denmark, United Kingdom, United States, New Zealand, Australia, The Netherlands, Sweden, Denmark, and Norway were included. We did quality assessment of the guidelines according to the AGREEMENT tool. We performed a meta-analysis assessing the effects of IA with a Doppler device vs. Pinard device using methods described in The Cochrane Handbook, and we performed an overall assessment of the summary of evidence using the GRADE approach.

Results

The searches generated 6408 hits of which 26 studies and 11 guidelines were included in the review. The studies described slightly different techniques for performing IA, and some did not provide detailed descriptions. Few of the studies provided details of normal and abnormal IA findings. All 11 guidelines recommended IA for low risk women, although they had slightly different recommendations on the frequency, timing, and duration for IA, and the FHR characteristics that should be observed. Four of the included studies, comprising 8436 women and their babies, were randomised controlled trials that evaluated the effect of IA with a Doppler device vs. a Pinard device. Abnormal FHRs were detected more often using the Doppler device than in those using the Pinard device (risk ratio 1.77; 95% confidence interval 1.29–2.43). There were no significant differences in any of the other maternal or neonatal outcomes. Four studies assessed the accuracy of IA findings. Normal FHR was easiest to identify correctly, whereas identifying periodic FHR patterns such as decelerations and saltatory patterns were more difficult.

Conclusion

Although IA is the recommended method, no trials have been published that evaluate protocols on how to perform it. Nor has any study assessed interrater agreements regarding interpretations of IA findings, and few have assessed to what degree clinicians can describe FHR patterns detected by IA. We found no evidence to recommend Doppler device instead of the Pinard for IA, or vice versa.

Cerebroplacental ratio assessment in early labor in uncomplicated term pregnancy and prediction of adverse perinatal outcome: prospective multicenter study

OBJECTIVE

It has been suggested that the use of Doppler ultrasound in term pregnancies with normal-sized fetuses is able to identify those at high risk of subclinical placental function impairment. The objective of this study was to evaluate the relationship between cerebroplacental ratio (CPR) measured in early labor and perinatal and delivery outcomes in a cohort of uncomplicated singleton term pregnancies.

METHODS

This was a prospective multicenter observational study conducted at three tertiary centers between January 2016 and July 2017. Low-risk term pregnancies, defined by the absence of maternal morbidity or pregnancy complication, accompanied by normal ultrasound and clinical screening of fetal growth in the third trimester, with spontaneous onset of labor were included. Umbilical artery (UA) and fetal middle cerebral artery (MCA) Doppler was assessed on admission for early labor. All measurements were performed in between uterine contractions and according to international standards. CPR was computed by dividing MCA pulsatility index by UA pulsatility index and converted into multiples of the median (MoM) in order to adjust for gestational age. Doctors and midwives involved in the clinical management of the women were blinded to the results of the Doppler evaluation. Mode of delivery and perinatal outcome were compared between pregnancies with reduced CPR MoM, defined as CPR MoM within the lowest decile of the study population, and those with normal CPR MoM. Receiver-operating characteristics curve analysis was used to assess the predictive performance of CPR for obstetric intervention due to fetal distress and composite adverse perinatal outcome.

RESULTS

Overall, 562 women were included. The rate of obstetric intervention for suspected fetal distress in labor was more than three times higher among cases with reduced CPR MoM compared to those with normal CPR MoM (9/54 (16.7%) vs 28/508 (5.5%); P = 0.004). Furthermore, a significantly higher rate of composite adverse perinatal outcome was found in fetuses with CPR MoM < 10^th percentile compared to those with CPR MoM ≥ 10^th percentile (6/54 (11.1%) vs 19/508 (3.7%); P = 0.012). CPR had low sensitivity and low positive predictive value for prediction of obstetric intervention due to fetal distress (24.3% and 18.0%, respectively) and composite adverse perinatal outcome (24.0% and 11.1%, respectively).

CONCLUSIONS

Data on a wide cohort of low-risk term pregnancies in early labor showed that, while reduced CPR is associated with a higher risk of obstetric intervention due to fetal distress and composite adverse perinatal outcome, it is a poor predictor of adverse perinatal outcome. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Segregation of Patients for Intrapartum Monitoring, using Robson's Classification

INTRODUCTION

Monitoring labour by intermittent or continuous foetal heart rate monitoring has been discussed widely in literature. Robson's classification has categorized pregnant women in ten groups. The study proposes to examine in which patients one must recommend continuous or intermittent foetal heart rate monitoring.

AIM

To study the effect of Continuous Electronic Foetal Monitoring (CEFM) on the overall rate of operative deliveries as well as the rate using Robson's classification and the neonatal outcome.

MATERIALS AND METHODS

After Institutional Review Board approval, low risk parturients with a reactive foetal heart rate at arrival in labour were prospectively analysed. Women with a previous caesarean section, those requiring elective caesarean section and having high risk factors were excluded. Patient details, history, examination findings and the method of monitoring, whether continuous or intermittent was noted. 1803 women were monitored by CEFM and 2107 by intermittent auscultation. In both the groups of intrapartum monitoring, suspected foetal distress was followed by immediate intervention in the form of caesarean section or operative vaginal delivery without resorting to any other monitoring methods such as foetal scalp blood sampling, as per the institutional policy. Comparison was based on the need for operative deliveries in view of presumed foetal distress and the neonatal outcome between the two groups of monitoring and further in each Robson's class. Results were assessed using IBM® SPSS Version 22.0, Chi-square test, considering p<0.05 as significant.

RESULTS

Operative deliveries in view of suspected foetal distress increased and the neonatal outcome was better with CEFM. Assessing in each Robson's class, only class 4A, 7A and 10A results were consistent with the overall outcome. In others (class 2A), women experienced reduced rate of operative deliveries and better neonatal outcome with CEFM. In yet others, there was no benefit with CEFM as there were increased operative deliveries without any difference in the neonatal outcome.

CONCLUSION

Segregation of patients for intrapartum monitoring using Robson's classification would result in decreased operative deliveries and a better neonatal outcome.

Critical Imperative for the Reform of British Interpretation of Fetal Heart Rate Decelerations: Analysis of FIGO and NICE Guidelines, Post-Truth Foundations, Cognitive Fallacies, Myths and Occam's Razor

Cardiotocography (CTG) has disappointingly failed to show good predictability for fetal acidemia or neonatal outcomes in several large studies. A complete rethink of CTG interpretation will not be out of place. Fetal heart rate (FHR) decelerations are the most common deviations, benign as well as manifestation of impending fetal hypoxemia/acidemia, much more commonly than FHR baseline or variability. Their specific nomenclature is important (center-stage) because it provides the basic concepts and framework on which the complex "pattern recognition" of CTG interpretation by clinicians depends. Unfortunately, the discrimination of FHR decelerations seems to be muddled since the British obstetrics adopted the concept of vast majority of FHR decelerations being "variable" (cord-compression). With proliferation of confusing waveform criteria, "atypical variables" became the commonest cause of suspicious/pathological CTG. However, National Institute for Health and Care Excellence (NICE) (2014) had to disband the "typical" and "atypical" terminology because of flawed classifying criteria. This analytical review makes a strong case that there are major and fundamental framing and confirmation fallacies (not just biases) in interpretation of FHR decelerations by NICE (2014) and International Federation of Gynecology and Obstetrics (FIGO) (2015), probably the biggest in modern medicine. This "post-truth" approach is incompatible with scientific practice. Moreover, it amounts to setting oneself for failure. The inertia to change could be best described as "backfire effect". There is abundant evidence that head-compression (and other non-hypoxic mediators) causes rapid rather than shallow/gradual decelerations. Currently, the vast majority of decelerations are attributed to unproven cord compression underpinned by flawed disproven pathophysiological hypotheses. Their further discrimination based on abstract, random, trial and error criteria remains unresolved suggesting a false premise to begin with. This is not surprising considering that the commonest pathophysiology of intrapartum hypoxemia is contraction-induced reduction in uteroplacental perfusion (sometimes already compromised) and not cord compression at all. This distorted categorization causes confusion, false-alarm fatigue and difficulty in focusing on real pathological decelerations making CTG interpretation dysfunctional ultimately compromising patient safety. Obstetricians/midwives should demand reverting to the previous more scientific British categorization of decelerations based solely on time relationship to contractions as advocated by the pioneers like Hon and Caldeyro-Barcia, rather than accepting the current "post-truth" scenario.

Intermittent auscultation (IA) of fetal heart rate in labour for fetal well-being

BACKGROUND

The goal of fetal monitoring in labour is the early detection of a hypoxic baby. There are a variety of tools and methods available for intermittent auscultation (IA) of the fetal heart rate (FHR). Low- and middle-income countries usually have only access to a Pinard/Laënnec or the use of a hand-held Doppler device. Currently, there is no robust evidence to guide clinical practice on the most effective IA tool to use, timing intervals and length of listening to the fetal heart for women during established labour.

OBJECTIVES

To evaluate the effectiveness of different tools for IA of the fetal heart rate during labour including frequency and duration of auscultation.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (19 September 2016), contacted experts and searched reference lists of retrieved articles.

SELECTION CRITERIA

All published and unpublished randomised controlled trials (RCTs) or cluster-RCTs comparing different tools and methods used for intermittent fetal auscultation during labour for fetal and maternal well-being. Quasi-RCTs, and cross-over designs were not eligible for inclusion.

DATA COLLECTION AND ANALYSIS

All review authors independently assessed eligibility, extracted data and assessed risk of bias for each trial. Data were checked for accuracy.

MAIN RESULTS

We included three studies (6241 women and 6241 babies), but only two studies are included in the meta-analyses (3242 women and 3242 babies). Both were judged as high risk for performance bias due to the inability to blind the participants and healthcare providers to the interventions. Evidence was graded as moderate to very low quality; the main reasons for downgrading were study design limitations and imprecision of effect estimates. Intermittent Electronic Fetal Monitoring (EFM) using Cardiotocography (CTG) with routine Pinard (one trial)There was no clear difference between groups in low Apgar scores at five minutes (reported as < six at five minutes after birth) (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.24 to 1.83, 633 babies, very low-quality evidence). There were no clear differences for perinatal mortality (RR 0.88, 95% CI 0.34 to 2.25; 633 infants, very low-quality evidence). Neonatal seizures were reduced in the EFM group (RR 0.05, 95% CI 0.00 to 0.89; 633 infants, very low-quality evidence). Other important infant outcomes were not reported: mortality or serious morbidity (composite outcome), cerebral palsy or neurosensory disability. For maternal outcomes, women allocated to intermittent electronic fetal monitoring (EFM) (CTG) had higher rates of caesarean section for fetal distress (RR 2.92, 95% CI 1.78 to 4.80, 633 women, moderate-quality evidence) compared with women allocated to routine Pinard. There was no clear difference between groups in instrumental vaginal births (RR 1.46, 95% CI 0.86 to 2.49, low-quality evidence). Other outcomes were not reported (maternal mortality, instrumental vaginal birth for fetal distress and or acidosis, analgesia in labour, mobility or restriction during labour, and postnatal depression). Doppler ultrasonography with routine Pinard (two trials)There was no clear difference between groups in Apgar scores < seven at five minutes after birth (reported as < six in one of the trials) (average RR 0.76, 95% CI 0.20 to 2.87; two trials, 2598 babies, I2 = 72%, very low-quality evidence); there was high heterogeneity for this outcome. There was no clear difference between groups for perinatal mortality (RR 0.69, 95% CI 0.09 to 5.40; 2597 infants, two studies, very low-quality evidence), or neonatal seizures (RR 0.05, 95% CI 0.00 to 0.91; 627 infants, one study, very low-quality evidence). Other important infant outcomes were not reported (cord blood acidosis, composite of mortality and serious morbidity, cerebral palsy, neurosensory disability). Only one study reported maternal outcomes. Women allocated to Doppler ultrasonography had higher rates of caesarean section for fetal distress compared with those allocated to routine Pinard (RR 2.71, 95% CI 1.64 to 4.48, 627 women, moderate-quality evidence). There was no clear difference in instrumental vaginal births between groups (RR 1.35, 95% CI 0.78 to 2.32, 627 women, low-quality evidence). Other maternal outcomes were not reported. Intensive Pinard versus routine Pinard (one trial)One trial compared intensive Pinard (a research midwife following the protocol in a one-to-one care situation) with routine Pinard (as per protocol but midwife may be caring for more than one woman in labour). There was no clear difference between groups in low Apgar score (reported as < six this trial) (RR 0.90, 95% CI 0.35 to 2.31, 625 babies, very low-quality evidence). There were also no clear differences identified for perinatal mortality (RR 0.56, 95% CI 0.19 to 1.67; 625 infants, very low-quality evidence), or neonatal seizures (RR 0.68, 95% CI 0.24 to 1.88, 625 infants, very low-quality evidence)). Other infant outcomes were not reported. For maternal outcomes, there were no clear differences between groups for caesarean section or instrumental delivery (RR 0.70, 95% CI 0.35 to 1.38, and RR 1.21, 95% CI 0.69 to 2.11, respectively, 625 women, both low-quality evidence)) Other outcomes were not reported.

AUTHORS' CONCLUSIONS

Using a hand-held (battery and wind-up) Doppler and intermittent CTG with an abdominal transducer without paper tracing for IA in labour was associated with an increase in caesarean sections due to fetal distress. There was no clear difference in neonatal outcomes (low Apgar scores at five minutes after birth, neonatal seizures or perinatal mortality). Long-term outcomes for the baby (including neurodevelopmental disability and cerebral palsy) were not reported. The quality of the evidence was assessed as moderate to very low and several important outcomes were not reported which means that uncertainty remains regarding the use of IA of FHR in labour.As intermittent CTG and Doppler were associated with higher rates of caesarean sections compared with routine Pinard monitoring, women, health practitioners and policy makers need to consider these results in the absence of evidence of short- and long-term benefits for the mother or baby.Large high-quality randomised trials, particularly in low-income settings, are needed. Trials should assess both short- and long-term health outcomes, comparing different monitoring tools and timing for IA.

Imperative for improvements and international convergence of intrapartum fetal monitoring: A bird’s eye view

Intrapartum fetal monitoring has been criticized for the lack of evidence of improvement in fetal outcome despite causing increased operative intervention. Paradoxically, cardiotocography (CTG) has been a major driver for litigation for neonatal neurological injury. This analytical review tries to explore why extensive clinical studies and trials over 50 years have failed to demonstrate or bring about significant improvement in intrapartum fetal monitoring. There seems a need for significant reform. International congruence on most aspects of CTG interpretation [definitions of fetal heart rate (FHR) parameters, CTG recording speed, 3-tier systems, etc.] is highly desirable to facilitate future meaningful clinical studies, evaluation and progress in this field. The FHR changes are non-specific and poor surrogate for fetal well-being. As a compromise for maintaining low false-negative results for fetal acidemia, a high false-positive value may have to be accepted. The need for redefining the place of adjuvant tests of fetal well-being like fetal blood sampling or fetal electrocardiography (ECG) is discussed. The FHR decelerations are often deterministic (center-stage) in CTG interpretation and 3-tier categorization. It is discussed if their scientific and physiological classification (avoiding framing and confirmation biases) may be best based on time relationship to uterine contractions alone. This may provide a more sound foundation which could improve the reliability and further evolution of 3-tier systems. Results of several trials of fetal ECG (STAN) have been inconclusive and a need for a fresh approach or strategy is considered. It is hoped that the long anticipated Computer-aided analysis of CTG will be more objective and reliable (overcome human factors) and will offer valuable support or may eventually replace visual CTG interpretation. In any case, the recording and archiving all CTGs digitally and testing cord blood gases routinely in every delivery would be highly desirable for future research. This would facilitate well designed retrospective studies which can be very informative especially when prospective randomised controlled trials are often difficult and resource-intensive.