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Intrapartum assessment of fetal well-being

2017; Elsevier BV; Volume: 17; Issue: 12 Linguagem: Inglês

10.1093/bjaed/mkx034

2058-5357

Gayani Jayasooriya, Veronica Djapardy,

Maternal and Perinatal Health Interventions

Key points•Despite electronic intrapartum monitoring of the fetal heart rate being firmly established in clinical practice it is experiencing rising levels of scrutiny as a sole decision tool in labour.•Interpretation of the cardiotocograph requires a systematic approach, with an appreciation of clinical context.•The National Institute for Clinical Care Excellence (NICE) and other institutions worldwide have produced guidelines to aid classification of the cardiotocograph.•Inter and intra-observer variation exists when interpreting findings of the cardiotocograph.•Adjunctive techniques to enhance clinical decision making during labour are constantly evolving. •Despite electronic intrapartum monitoring of the fetal heart rate being firmly established in clinical practice it is experiencing rising levels of scrutiny as a sole decision tool in labour.•Interpretation of the cardiotocograph requires a systematic approach, with an appreciation of clinical context.•The National Institute for Clinical Care Excellence (NICE) and other institutions worldwide have produced guidelines to aid classification of the cardiotocograph.•Inter and intra-observer variation exists when interpreting findings of the cardiotocograph.•Adjunctive techniques to enhance clinical decision making during labour are constantly evolving. National guidelines for cardiotocograph (CTG) interpretation have undergone significant changes in the past decade, and their role in predicting fetal well-being and outcomes has come under increasing scrutiny.1Sholapurkar SL Limits of current cardiotocography interpretation call for a major rethink.Am J Obstet Gynecol. 2017; 217: 92-93Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar,2Nelson KB Sartwelle TP Rouse DJ Electronic fetal monitoring, cerebral palsy, and caesarean section: assumptions versus evidence.Br Med J. 2016; 355: i6405Crossref PubMed Scopus (37) Google Scholar Accordingly, a survey endorsed by the Obstetric Anaesthetists' Association in 20163Jafri SDK Evans E Survey of CTG interpretation and training amongst obstetric anaesthetists.Available from https://www.stgeorges.nhs.uk/wp-content/uploads/2014/07/CTG-Poster-2016-1.pdfDate: 2016Google Scholar revealed a desire for continued education in interpretation of the CTG. This article will briefly refresh the physiology of fetal heart rate control, principles of CTG interpretation, its place in current evidence-based practice, and expand on complementary and emerging techniques of assessing fetal well-being in labour. Mechanisms of fetal heart rate control include the sinoatrial and atrioventricular nodes and cardiac conducting tissue. The fetal parasympathetic nervous system reaches maturity by term, whereas sympathetic nervous system development is still ongoing. As pregnancy progresses, this maturation of vagal innervation manifests as a decline in resting fetal heart rate and an increase in baseline variability. This has implications for the interpretation of fetal heart rate patterns at varying gestations. Other factors networked in fetal heart rate control include baroreceptors, chemoreceptors, circulating catecholamines, and other endocrine factors.4Freeman RKGT Nageotte MP Miller LA Fetal Heart Rate Monitoring.4th Edn. Lippincott, Williams and Wilkins, Philladelphia, USA2012Google Scholar Thus, fetal heart rate is predominantly a product of the intricate balance of the autonomic nervous system, with influences extrinsic to the heart, such as humoral factors, also playing a role. The fetus is conditioned to thrive in a mildly hypoxic and acidic environment. Oxygen exchange between the mother and the fetus is facilitated by this relative gradient. The insufficient supply of oxygen leads to changes in fetal pH- which then subsequently results in signs of distress in the fetus. One such sign is a change in fetal heart rate, caused by the impact of hypoxia and acidosis on the control mechanisms outlined above.4Freeman RKGT Nageotte MP Miller LA Fetal Heart Rate Monitoring.4th Edn. Lippincott, Williams and Wilkins, Philladelphia, USA2012Google Scholar Thus, the premise of electronic fetal monitoring (EFM) rests on the assumption that fetal heart rate is a reflection of fetal oxygenation status. Correct functioning of the fetomaternal circulation, uteroplacental exchange, and fetal factors have implications for fetal oxygenation. Any inadequacy of these factors may cause fetal compromise, which will be exaggerated in labour, where with every uterine contraction a period of reduced uteroplacental perfusion ensues. The purpose of intrapartum fetal heart rate monitoring is to detect episodes of hypoxia and prevent neonatal morbidity and mortality. Intermittent auscultation was used as early as the 1800s for evaluating fetal well-being, and the criteria for fetal distress were established by the mid-1850s.4Freeman RKGT Nageotte MP Miller LA Fetal Heart Rate Monitoring.4th Edn. Lippincott, Williams and Wilkins, Philladelphia, USA2012Google Scholar Routine use of EFM began in the 1970s to prevent consequences of hypoxia, such as cerebral palsy or hypoxaemic encephalopathy, despite a paucity of efficacy data.2Nelson KB Sartwelle TP Rouse DJ Electronic fetal monitoring, cerebral palsy, and caesarean section: assumptions versus evidence.Br Med J. 2016; 355: i6405Crossref PubMed Scopus (37) Google Scholar Although the rates of these complications have declined, there is very little evidence to suggest that this has been as a direct result of EFM. A Cochrane review5Alfirevic Z Devane D Gyte GM Cuthbert A Continuous cardiotocography (CTG) as a form of electronic fetal monitoring (EFM) for fetal assessment during labour.Cochrane Database Syst Rev. 2017; 2 (CD006066.)PubMed Google Scholar concluded that compared with intermittent auscultation, continuous CTG showed no significant difference in perinatal death and cerebral palsy rates. There was a reduced neonatal seizure rate with CTG use, but the relationship of early neonatal seizures to long-term disability is not well established. It is worth noting that most studies in the review were conducted before the early 1990s and only two were considered high quality. The authors also comment on an increased likelihood of intervention with CTG. As surgical delivery is known to increase risks to mothers in both the short term and the long term, this raises questions about the risk–benefit equilibrium of CTG monitoring. Importantly, no trial to date has compared CTG with no monitoring. This alludes to the fact that monitoring fetal well being in labour by some means is now considered standard practice, which would seem unethical to deny to a parturient. This disconnect of current 'best evidence', with perceived benefit in observational practice, compounded by costs of negligence claims in maternity care,2Nelson KB Sartwelle TP Rouse DJ Electronic fetal monitoring, cerebral palsy, and caesarean section: assumptions versus evidence.Br Med J. 2016; 355: i6405Crossref PubMed Scopus (37) Google Scholar,6Kmietowicz Z NHS in England paid out £3.1bn in compensation claims linked to maternity care in past decade.Br Med J. 2012; 345: e7290Crossref PubMed Scopus (3) Google Scholar perpetuates the ubiquitous nature of EFM. The answer to best practice may lie in the measured use of this technology, a standardized approach to definition and interpretation, combined with complementary techniques to provide context–in fact, as some authors suggest, a complete overhaul of the way CTGs are interpreted1Sholapurkar SL Limits of current cardiotocography interpretation call for a major rethink.Am J Obstet Gynecol. 2017; 217: 92-93Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar or, at the very least, the abandonment of this technique as a root cause of litigation.2Nelson KB Sartwelle TP Rouse DJ Electronic fetal monitoring, cerebral palsy, and caesarean section: assumptions versus evidence.Br Med J. 2016; 355: i6405Crossref PubMed Scopus (37) Google Scholar,7Sartwelle TP Electronic fetal monitoring: a bridge too far.J Leg Med. 2012; 33: 313-379Crossref PubMed Scopus (32) Google Scholar National Institute for Health and Care Excellence (NICE) guidelines8NICE National Institute for Health and Clinical Excellence (2014). Intrapartum care—care of healthy women and their babies during childbirth. Clinical guideline [CG190]. 1.10 Monitoring during labour. 2014 (Updated 2017).Available from https://www.nice.org.uk/guidance/cg190/chapter/recommendations-monitoring-during-labourGoogle Scholar suggest that with the high false-positive rate of CTG, its role in low-risk labour is not established. Here, it advocates the use of intermittent auscultation (pinard or hand-held Doppler) at specific intervals, with the aim of escalating monitoring if concerning features arise. A Doppler ultrasound transducer and pressure transducer are placed on the maternal abdomen, which monitor fetal heart rate and the frequency and strength of uterine contractions, respectively. These variables are then plotted against time on graph paper (Fig. 1). NICE has recently updated the list of risk factors that warrant continuous CTG during labour to include oxytocin use and the establishment and maintenance of regional anaesthesia.8NICE National Institute for Health and Clinical Excellence (2014). Intrapartum care—care of healthy women and their babies during childbirth. Clinical guideline [CG190]. 1.10 Monitoring during labour. 2014 (Updated 2017).Available from https://www.nice.org.uk/guidance/cg190/chapter/recommendations-monitoring-during-labourGoogle Scholar The assessment and interpretation of CTGs require a simple, systematic approach. The fetal heart rate is assessed for four features (Table 1) before categorizing the overall impression of the trace. Various systems exist;9American College of Obstetrics and Gynecology (ACOG) Practice bulletin no. 116: Management of intrapartum fetal heart rate tracings.Obstet Gynecol. 2010; 116: 1232-1240Crossref PubMed Scopus (108) Google Scholar,10Ayres-de-Campos D Spong CY Chandraharan E Panel FIFMEC FIGO consensus guidelines on intrapartum fetal monitoring: cardiotocography.Int J Gynaecol Obstet. 2015; 131: 13-24Crossref PubMed Scopus (393) Google Scholar however, here, we will discuss the classification system in the 2014 NICE Guidance (updated 2017).8NICE National Institute for Health and Clinical Excellence (2014). Intrapartum care—care of healthy women and their babies during childbirth. Clinical guideline [CG190]. 1.10 Monitoring during labour. 2014 (Updated 2017).Available from https://www.nice.org.uk/guidance/cg190/chapter/recommendations-monitoring-during-labourGoogle ScholarTable 1Description of cardiotocograph features. NICE guideline on intrapartum care for healthy women and babies.8NICE National Institute for Health and Clinical Excellence (2014). Intrapartum care—care of healthy women and their babies during childbirth. Clinical guideline [CG190]. 1.10 Monitoring during labour. 2014 (Updated 2017).Available from https://www.nice.org.uk/guidance/cg190/chapter/recommendations-monitoring-during-labourGoogle Scholar *Regard the following as concerning characteristics of variable decelerations: lasting more than 60 s; reduced baseline variability within the deceleration; failure to return to baseline; biphasic (W) shape; no shouldering (shouldering is a brief increase in fetal heart rate from baseline immediately before and after a deceleration, thus giving the deceleration the appearance of having 'shoulders'). †Although a baseline fetal heart rate between 100 and 109 beats min−1 is a non-reassuring feature, continue usual care if there is normal baseline variability and no variable or late decelerationsFeatures of CTGBaseline (beats min−1)Baseline variability (beats min−1)DecelerationsReassuring110–1605–25 •None or early•Variable decelerations with no concerning characteristics* <90 minNon-reassuring 100–109†OR161–180 25 for up to 15–25 min •Variable decelerations with no concerning characteristics* ≥90 minOR •Variable decelerations with any concerning characteristics* in up to 50% of contractions for ≥30 minOR •Variable decelerations with any concerning characteristics* in over 50% of contractions <30 minOR •Late decelerations in over 50% of contractions for <30 min, with no maternal or fetal clinical risk factors such as vaginal bleeding or significant meconiumAbnormal Below 100ORAbove 180 25 for more than 30 minORSinusoidal •Variable decelerations with any concerning characteristics* in over 50% of contractions for 30 min (or less if any maternal or fetal clinical risk factors)OR •Late decelerations for 30 min (or less if any maternal or fetal clinical risk factors)OR •Acute bradycardia or a single prolonged deceleration lasting 3 min or more Open table in a new tab Normal fetal heart rate at term is 110–160 beats min−1. The baseline is judged by looking at the mean heart rate over 10 min. A rate >160 beats min−1 is classified as a tachycardia and a rate 3 min. Clinical examination reveals a cervix which is 2 cm dilated, and a decision is made to proceed to Caesarean section immediately. Note how recording the maternal pulse helps differentiate fetal and maternal heart rates.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Variability refers to minor fluctuations in baseline fetal heart rate, which can be irregular in amplitude and frequency (Fig. 2). A normal variability is 5–25 beats min−1 and is measured from the peak to a trough of a recording during 1 min. A variability 25 beats min−1 is marked variability. Both extremes are associated with fetal hypoxic states and innocuous states, e.g. quiescence/sleep (reduced variability) or thumb sucking (marked variability). Persistent absence of variability is considered a pre-terminal feature and carries with it high probability of a hypoxic fetus. Sinusoidal variability is an oscillating pattern of three to five cycles per minute, which may indicate fetal anaemia or severe fetal hypoxia. However, similar patterns may present transiently in forceful thumb sucking (pseudo-sinusoidal). These are transient reductions in fetal heart rate (>15 beats min−1 reduction for at least 15 s), which can be further subdivided according to their shape, duration, and timing in relation to contractions. Early decelerations are uniform in shape and mirror the contraction. Thought to be a result of fetal head compression during a contraction, they should recover with relaxation of the uterus. Early decelerations are considered normal findings in labour. Although uniform and gradual in shape, they have a trough that occurs following the peak of a contraction (Fig. 3). These are a possible sign of reduced fetal oxygenation. These show a more sudden, steep reduction in fetal heart rate and are considered a sign of fetal hypoxia. The morphology of one deceleration may vary from the next, thus giving rise to its nomenclature. They can be further classified as uncomplicated ( 60 s). Any deceleration lasting more than 3 min falls into this category and usually prompts urgent delivery of the fetus (Fig. 3). Updated NICE guidance advises avoiding terminology such as typical and atypical as it can be confusing. It suggests, as a general rule of thumb, the longer and later the decelerations, the higher the risk of fetal acidosis, particularly if accompanied by a tachycardia and/or reduced baseline variability.8NICE National Institute for Health and Clinical Excellence (2014). Intrapartum care—care of healthy women and their babies during childbirth. Clinical guideline [CG190]. 1.10 Monitoring during labour. 2014 (Updated 2017).Available from https://www.nice.org.uk/guidance/cg190/chapter/recommendations-monitoring-during-labourGoogle Scholar Defined as transient increases in fetal heart rate (>15 beats min−1 for at least 15 s) these tend to be associated with fetal activity (Fig. 2). Although their presence is reassuring, absence in an otherwise normal CTG should not cause concern. Once an assessment of the four features is made, a CTG can be classed as normal, suspicious or pathological8NICE National Institute for Health and Clinical Excellence (2014). Intrapartum care—care of healthy women and their babies during childbirth. Clinical guideline [CG190]. 1.10 Monitoring during labour. 2014 (Updated 2017).Available from https://www.nice.org.uk/guidance/cg190/chapter/recommendations-monitoring-during-labourGoogle Scholar with the purpose of guiding management (Table 2). Despite this seemingly logical classification, inter- and intra-observer variability exists when interpreting recordings.11Sabiani L Le Du R Loundou A Intra- and interobserver agreement among obstetric experts in court regarding the review of abnormal fetal heart rate tracings and obstetrical management.Am J Obstet Gynecol. 2015; 213: 856.e1-856.e8Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar The range of classification systems have compounded the situation by introducing variability in definition of CTG characteristics and classification.12Santo S Ayres-de-Campos D Costa-Santos C et al.Agreement and accuracy using the FIGO, ACOG and NICE cardiotocography interpretation guidelines.Acta Obstet Gynecol Scand. 2017; 96: 166-175Crossref PubMed Scopus (46) Google Scholar In addition, technical difficulties such as loss of contact and inadvertent maternal pulse recording further hinder accuracy. Several practices have become commonplace to try to mitigate these inconsistencies, including a 'fresh eyes' or a 'buddy' approach to CTG interpretation.13Fitzpatrick T Holt L A ′buddy′ approach to CTG.Midwives. 2008; 11: 40-41PubMed Google Scholar Aides-mémoire for locally adopted classification systems, such as standardized CTG stickers, have also become routine.Table 2Management based on interpretation of CTG traces adapted from NICE guideline on intrapartum care for healthy women and babies. *If there are any concerns about the baby's well-being, be aware of the possible underlying causes and start one or more of the following conservative measures based on an assessment of the most likely cause(s): encourage the woman to mobilize or adopt an alternative position (and to avoid being supine); offer i.v. fluids if the woman is hypotensive; reduce contraction frequency by reducing or stopping oxytocin if it is being used and/or offering a tocolytic drug (a suggested regimen is subcutaneous terbutaline 0.25 mg). †Talk to the woman and her birth companion(s) about what is happeningCategoryDefinitionManagementNormalAll features are reassuring •Continue CTG†Suspicious1 Non-reassuring feature •Correct any underlying causes such as hypotension or uterine hyperstimulation•Start one or more conservative measures*•Inform an obstetrician or a senior midwife•Document a plan for reviewing the whole clinical picture and the CTG findings†AND2 Reassuring featuresPathological1 Abnormal feature •Obtain a review by an obstetrician and a senior midwife•Exclude acute events (e.g. cord prolapse, suspected placental abruption, or suspected uterine rupture)•Correct any underlying causes, such as hypotension or uterine hyperstimulation•Start one or more conservative measures*•If the CTG trace is still pathological after implementing conservative measures: •– obtain a further review by an obstetrician and a senior midwife•– offer digital fetal scalp stimulation and document the outcomeIf the cardiotocograph trace is still pathological after fetal scalp stimulation: – consider fetal blood sampling– consider expediting the birthOR2 Non-reassuring featuresNeed for urgent interventionAcute bradycardia or a single prolonged deceleration for 3 min or more •Urgently seek obstetric help•If there has been an acute event (e.g. cord prolapse, suspected placental abruption, or suspected uterine rupture) expedite the birth•Correct any underlying causes, such as hypotension or uterine hyperstimulation•Start one or more conservative measures*•Make preparations for an urgent birth•Expedite the birth if the acute bradycardia persists for 9 minIf the fetal heart rate recovers at any time up to 9 min, reassess any decision to expedite the birth, in discussion with the woman† Open table in a new tab Electronic interpretation of CTG tracings is sometimes utilized to supplement clinician analysis with the intention of a more objective assessment. However, recently published results of the INFANT study [randomized controlled trial (RCT) of >46 000 women] demonstrated no significant neonatal benefit, nor did it reveal any difference in mode or urgency of delivery when employing an electronic decision support tool to supplement clinician interpretation.14The INFANT Collaborative GroupComputerised interpretation of fetal heart rate during labour (INFANT): a randomised controlled trial.Lancet. 2017; 389: 1719-1729Abstract Full Text Full Text PDF PubMed Scopus (102) Google Scholar It has become understood that CTG interpretation is an imperfect science, and as such, adjuncts have been developed with the aim of enhancing clinical decision making. The fetal scalp electrode is placed on the fetal scalp. The fetal heart rate is derived from the R-R interval of the fetal electrocardiographic (fECG) trace picked up by the device. Although, placement can be difficult, it carries the risk of infection, and has the potential to become displaced, it may allow more reliable recording of fetal heart rate where trans-abdominal detection has been substandard. This involves taking fetal scalp blood into capillary tubes for analysis of fetal pH and/or lactate. Acquiring samples can be time-consuming, can be difficult, and may fail to yield an adequate sample for analysis. Additionally, it can be falsely reassuring in the presence of chorioamnionitis or thick meconium. Historically, while pH has been the measurement of interest, recently, the Royal College of Obstetricians and Gynaecologists (RCOG) has advocated measurement of lactate too.15Mowbray DRJ Nordström L Ofunne WN Akhtar S Is it Time for UK Obstetricians to Accept Fetal Scalp Lactate as an Alternative to Scalp pH? Scientific Impact.Available from https://www.rcog.org.uk/en/guidelines-research-services/guidelines/sip47/Date: 2015Google Scholar Although outcomes have been comparable with either method, there appears to be a higher chance of successfully obtaining a sample for lactate measurement, because of the smaller sample size required. Fetal blood sampling (FBS) should not be performed when the clinical picture suggests that delivery should be expedited regardless of the result. However, when uncertainty exists regarding the significance of CTG findings, the RCOG 15Mowbray DRJ Nordström L Ofunne WN Akhtar S Is it Time for UK Obstetricians to Accept Fetal Scalp Lactate as an Alternative to Scalp pH? Scientific Impact.Available from https://www.rcog.org.uk/en/guidelines-research-services/guidelines/sip47/Date: 2015Google Scholar and NICE8NICE National Institute for Health and Clinical Excellence (2014). Intrapartum care—care of healthy women and their babies during childbirth. Clinical guideline [CG190]. 1.10 Monitoring during labour. 2014 (Updated 2017).Available from https://www.nice.org.uk/guidance/cg190/chapter/recommendations-monitoring-during-labourGoogle Scholar recommend its use (Table 2). Digital fetal scalp simulation during the procedure can cause fetal heart accelerations, which may be a reassuring sign.8NICE National Institute for Health and Clinical Excellence (2014). Intrapartum care—care of healthy women and their babies during childbirth. Clinical guideline [CG190]. 1.10 Monitoring during labour. 2014 (Updated 2017).Available from https://www.nice.org.uk/guidance/cg190/chapter/recommendations-monitoring-during-labourGoogle Scholar This too requires placement of a sensor on the fetal presenting part. The literature suggests that fetal saturations ≥30% are reassuring, whereas <30% should prompt consideration of intervention.16East CE Begg L Colditz PB Lau R Fetal pulse oximetry for fetal assessment in labour.Cochrane Database Syst Rev. 2014; 10 (CD004075.)Google Scholar A Cochrane review of fetal pulse oximetry (FPO) to supplement CTG concluded that its use did not appear to enhance clinical practice16East CE Begg L Colditz PB Lau R Fetal pulse oximetry for fetal assessment in labour.Cochrane Database Syst Rev. 2014; 10 (CD004075.)Google Scholar and in keeping with this the use of FPO appears to have ceased. Hypoxaemia alters characteristics of the fECG (P-R interval, T:QRS ratio and ST segment).17Neilson JP Fetal electrocardiogram (ECG) for fetal monitoring during labour.Cochrane Database Syst Rev. 2015; 12 (CD000116.)Google Scholar When this technique is used, it is with the aid of automated ST analysis (STAN®) software which looks at the CTG and fECG concurrently. The analysis of the fECG using STAN® requires a scalp electrode to be placed. A Cochrane review17Neilson JP Fetal electrocardiogram (ECG) for fetal monitoring during labour.Cochrane Database Syst Rev. 2015; 12 (CD000116.)Google Scholar looked at RCTs analysing the effect of using fECG to complement CTG interpretation. It concluded that combining fECG with CTG made no difference to the number of Caesarean sections, fetal pH, neonatal encephalopathy, neonatal intubation, or APGAR scores compared with CTG alone. There was a reduced likelihood of performing FBS and a marginal reduction in operative vaginal delivery rates with fECG use. In keeping with this, a subsequent RCT of over 11 000 deliveries demonstrated no impact on operative delivery rates or perinatal outcomes.18Belfort MA Saade GR Thom E et al.A randomized trial of intrapartum fetal ECG ST-segment analysis.N Engl J Med. 2015; 373: 632-641Crossref PubMed Scopus (105) Google Scholar The current NICE guideline does not make a recommendation on the use of STAN®.8NICE National Institute for Health and Clinical Excellence (2014). Intrapartum care—care of healthy women and their babies during childbirth. Clinical guideline [CG190]. 1.10 Monitoring during labour. 2014 (Updated 2017).Available from https://www.nice.org.uk/guidance/cg190/chapter/recommendations-monitoring-during-labourGoogle Scholar Transabdominal ultrasound scanning is now commonplace in the setting of fetal distress in labour. The ease of use, combined with minimal risk profile, makes it a desirable tool, and the ability to visualize fetal cardiac activity rapidly and directly is useful for timely decision making. Another emergent setting in which ultrasound is used is decision making before and during an operative vaginal delivery (e.g. forceps, vacuum cup). The use of ultrasound to correctly identify fetal head position and orientation can help select an appropriate and safe technique for assisted delivery.19Dębska M Kretowicz P Dębski R Intrapartum sonography—eccentricity or necessity?.J Ultrason. 2015; 15: 125-136Crossref PubMed Google Scholar Ultrasound can also assess fetal cardiac activity during these deliveries. Evidence is accumulating that ultrasound during labour may predict the need for Caesarean section. Intrapartum ultrasound has been the focus of studies evaluating how several measured parameters affect the likelihood of successful vaginal delivery.20Ahn KH Oh MJ Intrapartum ultrasound: a useful method for evaluating labor progress and predicting operative vaginal delivery.Obstet Gynecol Sci. 2014; 57: 427-435Crossref PubMed Google Scholar This technique not only provides objective and quantitative data but also has shown high inter- and intra-observer reliability.20Ahn KH Oh MJ Intrapartum ultrasound: a useful method for evaluating labor progress and predicting operative vaginal delivery.Obstet Gynecol Sci. 2014; 57: 427-435Crossref PubMed Google Scholar Despite the aforementioned limitations of CTG, it continues to form an established component of the assessment of a fetus during labour. Litigation, combined with the perceived benefits of this technique, is likely to perpetuate its use for the foreseeable future. Abandonment of intrapartum EFM is highly unlikely without widespread uptake of an acceptable alternative method of monitoring, which at present seems a distant occurrence. It is, therefore, imperative that anaesthetists, as part of a multidisciplinary team, have an appreciation of the currently available techniques for assessing intrapartum fetal well-being.