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What is the "normal" fetal heart rate?

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Aim. There is no consensus about the normal fetal heart rate. Current international guidelines recommend for the normal fetal heart rate (FHR) baseline different ranges of 110 to 150 beats per minute (bpm) or 110 to 160 bpm. We started with a precise definition of “normality” and performed a retrospective computerized analysis of electronically recorded FHR tracings. Methods. We analyzed all recorded cardiotocography tracings of singleton pregnancies in three German medical centers from 2000 to 2007 and identified 78,852 tracings of sufficient quality. For each tracing, the baseline FHR was extracted by eliminating accelerations/decelerations and averaging based on the “delayed moving windows” algorithm. After analyzing 40% of the dataset as “training set” from one hospital generating a hypothetical normal baseline range, evaluation of external validity on the other 60% of the data was performed using data from later years in the same hospital and externally using data from the two other hospitals. Results. Based on the training data set, the “best” FHR range was 115 or 120 to 160 bpm. Validation in all three data sets identified 120 to 160 bpm as the correct symmetric “normal range”. FHR decreases slightly during gestation. Conclusions. Normal ranges for FHR are 120 to 160 bpm. Many international guidelines define ranges of 110 to 160 bpm which seem to be safe in daily practice. However, further studies should confirm that such asymmetric alarm limits are safe, with a particular focus on the lower bound, and should give insights about how to show and further improve the usefulness of the widely used practice of CTG monitoring.
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... Fetal Heart Rate (FHR) is measurable from around six weeks gestational age and varies during gestation, increasing to around 170 beats per minute (bpm) at 10 weeks and decreasing to around 130 bpm at term. 1,2 Ultrasonography is highly valuable for antenatal screening and fetal monitoring programmes worldwide. 3e7 Fetal monitoring is a way of checking oxygenation. ...
... From all indications, there is no consensus about the normal FHR worldwide. 1 Due to the variability of FHR values, 36,37 it is imperative to understand the pattern of sonographic FHR among healthy women with a view to providing reliable evidence-based FHR values for fetal autonomic system development and better management of pregnancy. Consequently, the aim of this study was to evaluate sonographic FHR across the three trimesters among healthy low-risk pregnant women presenting for routine antenatal care and also explore the possibility of predicting gestational age using FHR measurement. ...
... The American Congress of Obstetricians and Gynaecologists, Eunice Kennedy Shriver Institute for Child Health and Human Development, National Institute for Health and Clinical Excellence, Royal Australian and New Zealand College of Obstetricians and Gynaecologists and other international obstetrics societies have suggested a wide range of normal FHR for fetal monitoring between 110 and 160 bpm. 43e49 In 2013, Pilder von Steinburg et al., 1 argued that although these guidelines are widely recommended, they were predominantly based on expert opinion rather than evidence. Consequently, they evaluated 1.5 billion CTGs from 78852 tracings recorded from three German hospitals and proposed that normal FHR should lie between 120 and 160bpm. 1 Park et al., also supported this view in a study of 4589 CTG FHR tracings in Korea. ...
Article
Introduction The aim of this study was to evaluate and report normal sonographic FHR values among low-risk singleton women across the three trimesters of pregnancy and determine FHR role in gestational age prediction. Method A prospective cross-sectional study of 2727 low-risk singleton pregnant women was undertaken. FHR measurements were obtained by a consultant radiologist and three experienced sonographers using transabdominal approach from January 2019 to December 2020. Two FHR measurements were taken for each participant. The fetal lie and presentation were also documented in the first trimester. Data were analysed using SPSS version 24 (IBM, Armonk, NY, USA). Result The maternal mean ± SD age was 25.8 ± 6.5 years and mean FHR for first, second and third trimesters were 151 ± 16, 145 ± 6 and 125±6 bpm respectively. The mean ± SD gestational age were 10 ± 2, 19 ± 3 and 34 ± 2 weeks for the first, second and third trimester respectively. Using ANOVA, there were statistically significant differences in FHR across the three trimesters (p ≤ 0.05). A positive correlation existed between maternal age and FHR (r = 0.57, p ≤ 0.05). Conclusion This study has established normal values for FHR in first, second and third trimester respectively. Referring physicians, radiologists, sonographers, obstetricians and gynaecologists may consider FHR of (135–167) bpm (139–151) bpm and (119–131) bpm as normal FHR ranges for the first, second and third trimester respectively. This study has also revealed the possibility of gestational age prediction using FHR with the equation [Gestational Age = 87.8 – (0.47) FHR]. Implications for practice This paper provides the most up-to-date sonographic FHR recommendations for fetal management. More importantly, findings from this study also suggests that ultrasound practitioners can use FHR measurements as a reliable alternative for fetal dating.
... Dividing the gestational age into two periods less than or more than 30 weeks provides better analysis of the attention and λ p with respect to fetal heart growth. In our findings ( Figures 5C,D), both methods showed a drop in the [1:2] coupling scenario going from the first to the second gestational period, which is an evidence on proper fetal cardiac development that reaches higher heart rates than the maternal (50). Additionally, the [2:3] coupling scenario with deep learning attention had an increasing pattern with gestational age as an indication of more fetal heart activity closer to late pregnancy, which matches our previous findings (49). ...
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In the last two decades, stillbirth has caused around 2 million fetal deaths worldwide. Although current ultrasound tools are reliably used for the assessment of fetal growth during pregnancy, it still raises safety issues on the fetus, requires skilled providers, and has economic concerns in less developed countries. Here, we propose deep coherence, a novel artificial intelligence (AI) approach that relies on 1 min non-invasive electrocardiography (ECG) to explain the association between maternal and fetal heartbeats during pregnancy. We validated the performance of this approach using a trained deep learning tool on a total of 941 one minute maternal-fetal R-peaks segments collected from 172 pregnant women (20–40 weeks). The high accuracy achieved by the tool (90%) in identifying coupling scenarios demonstrated the potential of using AI as a monitoring tool for frequent evaluation of fetal development. The interpretability of deep learning was significant in explaining synchronization mechanisms between the maternal and fetal heartbeats. This study could potentially pave the way toward the integration of automated deep learning tools in clinical practice to provide timely and continuous fetal monitoring while reducing triage, side-effects, and costs associated with current clinical devices.
... Parameters assessed in the EFM tracing (ie, baseline, frequency, variability, accelerations and decelerations) are drawn from different scientific bases, ranging from detailed knowledge of origin via experimental animal studies (eg, umbilical cord compression and variable decelerations) 1 to consensus based on retrospective observational studies (eg, normal interval of the baseline frequency). 2 The strength of EFM is its high sensitivity with few false-negative results. One limitation is the low specificity with many false-positive results, which lead to interventions and associated risks for the woman without benefit for the infant. ...
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Introduction: A revised intrapartum cardiotocography (CTG) classification was introduced in Sweden in 2017. The aims of the revision were to adapt to the international guideline published in 2015 and to adjust the classification of CTG patterns to current evidence regarding intrapartum fetal physiology. This study aimed to investigate adverse neonatal outcomes before and after implementation of the revised CTG classification. Material and methods: A before-and-after design was used. Cohort I (n = 160 210) included births from June 1, 2014 through May 31, 2016 using the former CTG classification, and cohort II (n = 166 558) included births from June 1, 2018 through May 31, 2020 with the revised classification. Data were collected from the Swedish Pregnancy and Neonatal Registers. The primary outcome was moderate to severe neonatal hypoxic ischemic encephalopathy (HIE 2-3). Secondary outcomes were birth acidemia (umbilical artery pH <7.05 and base excess < -12 mmol/L or pH <7.00), A-criteria for neonatal hypothermia treatment, 5-min Apgar scores <4 and <7, neonatal seizures, meconium aspiration, neonatal mortality and delivery mode. Logistic regression was used (period II vs period I), and results are presented as adjusted odds ratios (aORs) with 95% confidence intervals (95% CIs). Results: There were no statistically significant differences in HIE 2-3 (aOR 1.27; 95% CI 0.97-1.66), proportion of neonates meeting A-criteria for hypothermia treatment (aOR 0.96; 95% CI 0.89-1.04) or neonatal mortality (aOR 0.68; 95% CI 0.39-1.18) between the cohorts. Birth acidemia (aOR 1.36; 95% CI 1.25-1.48), 5-min Apgar scores <7 (aOR 1.27; 95% CI 1.18-1.36) and <4 (aOR 1.40; 95% CI 1.17-1.66) occurred more often in cohort II. The absolute risk difference for HIE 2-3 was 0.02% (95% CI 0.00-0.04). Operative delivery (vacuum or cesarean) rates were lower in cohort II (aOR 0.82; 95% CI 0.80-0.85 and aOR 0.94; 95% CI 0.91-0.97, respectively). Conclusions: Although not statistically significant, a small increase in the incidence of HIE 2-3 after implementation of the revised CTG classification cannot be excluded. Operative deliveries were fewer but incidences of acidemia and low Apgar scores were higher in the latter cohort. This warrants further in-depth analyses before a full re-evaluation of the revised classification can be made.
... The two steps are combined using the full Laplacian pyramid in the EVM method. 2 Temporal filtering: For each spatial band, band pass filtering is performed to extract the variation part of interest. Since infant's HR range is 110-160 BPM [34], we choose the ideal bandpass filter within 1.8333-2.6667 Hz to directly cut off the frequency band of interest, and avoid amplifying other frequency bands. ...
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Background Heart rate (HR) is an important vital sign for evaluating the physiological condition of a newborn infant. Recently, for measuring HR, novel RGB camera-based non-contact techniques have demonstrated their specific superiority compared with other techniques, such as dopplers and thermal cameras. However, they still suffered poor robustness in infants’ HR measurements due to frequent body movement. Methods This paper introduces a framework to improve the robustness of infants’ HR measurements by solving motion artifact problems. Our solution is based on the following steps: morphology-based filtering, region-of-interest (ROI) dividing, Eulerian video magnification and majority voting. In particular, ROI dividing improves ROI information utilization. The majority voting scheme improves the statistical robustness by choosing the HR with the highest probability. Additionally, we determined the dividing parameter that leads to the most accurate HR measurements. In order to examine the performance of the proposed method, we collected 4 hours of videos and recorded the corresponding electrocardiogram (ECG) of 9 hospitalized neonates under two different conditions—rest still and visible movements. Results Experimental results indicate a promising performance: the mean absolute error during rest still and visible movements are 3.39 beats per minute (BPM) and 4.34 BPM, respectively, which improves at least 2.00 and 1.88 BPM compared with previous works. The Bland-Altman plots also show the remarkable consistency of our results and the HR derived from the ground-truth ECG. Conclusions To the best of our knowledge, this is the first study aimed at improving the robustness of neonatal HR measurement under motion artifacts using an RGB camera. The preliminary results have shown the promising prospects of the proposed method, which hopefully reduce neonatal mortality in hospitals.
... Various methods are used for FHR assessment; however, the standard approach is based on measuring the blood flow in the umbilical cord by Doppler ultrasound [5,6]. Therefore, this study aimed to establish normal ranges of FHR values for healthy fetuses in Poland during gestation, as determined by ultrasound. ...
Article
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Conference Paper
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The aim of intrapartum continuous electronic fetal monitoring using a cardiotocograph (CTG) is to identify a fetus exposed to intrapartum hypoxic insults so that timely and appropriate action could be instituted to improve perinatal outcome. Features observed on a CTG trace reflect the functioning of somatic and autonomic nervous systems and the fetal response to hypoxic or mechanical insults during labour. Although, National Guidelines on electronic fetal monitoring exist for term fetuses, there is paucity of recommendations based on scientific evidence for monitoring preterm fetuses during labour. Lack of evidence-based recommendations may pose a clinical dilemma as preterm births account for nearly 8% (1 in 13) live births in England and Wales. 93% of these preterm births occur after 28 weeks, 6% between 22-27 weeks, and 1% before 22 weeks. Physiological control of fetal heart rate and the resultant features observed on the CTG trace differs in the preterm fetus as compared to a fetus at term making interpretation difficult. This review describes the features of normal fetal heart rate patterns at different gestations and the physiological responses of a preterm fetus compared to a fetus at term. We have proposed an algorithm "ACUTE" to aid management.
The purpose of the National Institutes of Health (NIH) research planning workshops are to assess the research status of clinically important areas. This article reports on a workshop, whose meetings were held between May 1995 and November 1996, in Bethesda, MD, and Chicago, IL. Its specific purpose was to develop standardized and unambiguous definitions for fetal heart rate (FHR) tracings. Their recommendations for interpreting FHR patterns are being published here, in JOGNN, and simultaneously by the American Journal of Obstetrics and Gynecology.
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In the most recent year for which data are available, approximately 3.4 million fetuses (85% of approximately 4 million live births) in the United States were assessed with electronic fetal monitoring (EFM), making it the most common obstetric procedure (1). Despite its widespread use, there is controversy about the efficacy of EFM, interobserver and intraobserver variability, nomenclature, systems for interpretation, and management algorithms. Moreover, there is evidence that the use of EFM increases the rate of cesarean deliveries and operative vaginal deliveries. The purpose of this document is to review nomenclature for fetal heart rate assessment, review the data on the efficacy of EFM, delineate the strengths and shortcomings of EFM, and describe a system for EFM classification. Copyright © July 2009 by the American College of Obstetricians and Gynecologists.
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The purpose of the National Institutes of Health research planning workshops is to assess the research status of clinically important areas. This article reports on a workshop whose meetings were held between May 1995 and November 1996 in Bethesda, Maryland, and Chicago, Illinois. Its specific purpose was to develop standardized and unambiguous definitions for fetal heart rate tracings. The recommendations for interpreting fetal hear? rate patterns are being published here and simultaneously by the Journal of Obstetric, Gynecologic, and Neonatal Nursing.
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There is controversy about the value of continuous versus intermittent auscultation of the fetal heart during labour, but there is no agreement on what constitutes normal heart rate of a term fetus. There are variations between the definitions adopted by different countries, and even within a single country. We propose 110-160 beats per minute for clinical use.
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Context: Numerous randomized controlled trials have demonstrated limited efficacy of intrapartum fetal heart rate monitoring in improving fetal outcome. A potential reason is the wide variability in clinical decision making seen with its use. Standardizing management of variant intrapartum fetal heart rate tracings may reduce this variability and lead to improvement in fetal outcome. Objective: We sought to develop notification guidelines and a management algorithm for variant intrapartum fetal heart rate tracings that improve fetal outcome and do not increase the operative delivery rate. Design: Outcomes for cases involving the use of our notification guidelines and management algorithm over six months (1181 deliveries) were compared with outcomes for historical control subjects (2247 deliveries). Main outcome measures: The main outcome measures were Apgar scores <7 and the operative delivery rate. Results: We found no change in fetal outcome or operative delivery rate. Conclusion: Our notification guidelines and management algorithm are safe and do not increase the operative delivery rate. A large multicenter trial is needed to demonstrate improvement in fetal outcome.