Electronic Fetal Heart Rate Monitoring Research Articles

Deep learning with information fusion and model interpretation for long-term prenatal fetal heart rate data

Long-term fetal heart rate (FHR) monitoring during the antepartum period, increasingly popularized by electronic FHR monitoring, represents a growing approach in FHR monitoring. This kind of continuous monitoring, in contrast to the short-term one, collects an extended period of fetal heart data. This offers a more comprehensive understanding of fetus’s conditions. However, the interpretation of long-term antenatal fetal heart monitoring is still in its early stages, lacking corresponding clinical standards. Furthermore, the substantial amount of data generated by continuous monitoring imposes a significant burden on clinical work when analyzed manually. To address above challenges, this study develops an automatic analysis system named LARA (Long-term Antepartum Risk Analysis system) for continuous FHR monitoring, combining deep learning and information fusion methods. LARA’s core is a well-established convolutional neural network (CNN) model. It processes long-term FHR data as input and generates a Risk Distribution Map (RDM) and Risk Index (RI) as the analysis results. We evaluate LARA on inner test dataset, the performance metrics are as follows: AUC 0.872, accuracy 0.816, specificity 0.811, sensitivity 0.806, precision 0.271, and F1 score 0.415. In our study, we observe that long-term FHR monitoring data with higher RI is more likely to result in adverse outcomes (p = 0.0021). In conclusion, this study introduces LARA, the first automated analysis system for long-term FHR monitoring, initiating the further explorations into its clinical value in the future.

The effect of continuous electronic fetal monitoring on mode of delivery and neonatal outcome among low-risk laboring mothers at Debre Markos comprehensive specialized hospital, Northwest Ethiopia.

Electronic fetal heart rate monitoring (EFM) has been widely used in obstetric practice for over 40 years to improve perinatal outcomes. Its popularity is growing in Ethiopia and other sub-Saharan African countries to reduce high perinatal morbidity and mortality rates. However, its impact on delivery mode and perinatal outcomes in low-risk pregnancies remains controversial. This study aimed to assess the effect of continuous EFM on delivery mode and neonatal outcomes among low-risk laboring mothers at Debre Markos Comprehensive Specialized Hospital, Northwest Ethiopia. A prospective follow-up study was conducted from November 20, 2023, to January 10, 2024. All low-risk laboring mothers meeting the inclusion criteria were included. Data were collected via pretested structured questionnaires and observation, then analyzed using Epi-data 4.6 and SPSS. The incidences of cesarean delivery and continuous EFM were compared using the chi-squared test and Fisher's exact test. The study found higher rates of instrumental-assisted vaginal delivery (7% vs. 2.4%) and cesarean sections (16% vs. 2%) due to unsettling fetal heart rate patterns in the continuous EFM group compared to the intermittent auscultation group. However, there were no differences in immediate neonatal outcomes between the groups. When compared to intermittent auscultation with a Pinard fetoscope, the routine use of continuous EFM among low-risk laboring mothers was associated with an increased risk of cesarean sections and instrumental vaginal deliveries, without significantly improving immediate newborn outcomes. However, it is important to note that our study faced significant logistical constraints due to the limited availability of EFM devices, which influenced our ability to use EFM comprehensively. Given these limitations, we recommend avoiding the routine use of continuous EFM for low-risk laboring mothers to help reduce the rising number of operative deliveries, particularly cesarean sections. Our findings should be interpreted with caution, and further research with adequate resources is needed to draw definitive conclusions.

Transcutaneous Discrimination of Fetal Heart Rate from Maternal Heart Rate: A Fetal Oximetry Proof-of-Concept.

Intrapartum care uses electronic fetal heart rate monitoring (EFHRM) for over 50years to indirectly assess fetal oxygenation. However, this approach has been associated with an increase in cesarean delivery rates and limited improvements in neonatal hypoxic outcome. To address these shortcomings, a novel transabdominal fetal pulse oximeter (TFO) is being developed to provide an objective measurement of fetal oxygenation. Previous studies have evaluated the performance of TFO on pregnant ewe. Building on the animal model, this study aims to determine whether TFO can successfully capture human fetal heart rate (FHR) signals during non-stress testing (NST) as a proof-of-concept. Eight ongoing pregnancies meeting specific inclusion criteria (18-40years old, singleton, and at least 36weeks' gestation) were enrolled with consent. Each study session was 15 to 20min long. Reference maternal heart rate (MHR) and FHR were obtained using finger pulse oximetry and cardiotocography for subsequent comparison. The overall root-mean-square error was 9.7BPM for FHR and 4.4 for MHR, while the overall mean-absolute error was 7.6BPM for FHR and 1.8 for MHR. Bland-Altman analysis displayed a mean bias ± standard deviation between TFO and reference of -3.9 ± 8.9BPM, with limits of agreement ranging from -21.4 to 13.6 BPM. Both maternal and fetal heart rate measurements obtained from TFO exhibited a p-value < 0.001, showing significant correlation with the reference. This proof-of-concept study successfully demonstrates that TFO can accurately differentiate maternal and fetal heart signals in human subjects. This achievement marks the initial step towards enabling fetal oxygen saturation measurement in humans using TFO.

Umbilical cord gas analysis: clinical implications of a comprehensive, contemporary determination of normal ranges

Umbilical cord gases are often used to assess the impact of labor and delivery on the fetus. However, no large series exists that reflects contemporary obstetrical practice or that analyzed blood gas ranges by route of delivery. Baseline, prelabor acid-base status in the human fetus is also poorly defined, rendering the assessment of blood gas changes during labor difficult. This study aimed to define normal umbilical cord gas and lactate values, stratified by mode of delivery, in a large contemporary series in which universal umbilical cord gas evaluation was dictated by protocol. This was a retrospective cohort study. We analyzed the umbilical cord gas and lactate data of an unselected population of infants born between March 2012 and April 2022 at a large teaching hospital. These values were then analyzed by mode of delivery and, for cesarean deliveries, by indication for cesarean delivery and type of anesthesia. Umbilical cord gas values from infants delivered by elective cesarean delivey under general anesthesia without labor were considered representative of baseline, prelabor values. Data were available for 45,475 infants. The median arterial pH values and interquartile ranges for vaginal births, elective cesarean deliveries without labor, and cesarean deliveries performed for fetal heart rate concerns were 7.27 (0.09), 7.27 (0.06), and 7.25 (0.09), respectively. Arterial lactate values for these same 3 groups were 4.1 (2.5), 2.5 (1.2), and 4.0 (2.8) mmoles/L, respectively. Because of the very large sample size, most comparisons yielded differences that were statistically significant, but clinically irrelevant. Of all the infants, 14% had an arterial pH <7.20; a pH value of 7.1 represents 2 standard deviations from the mean. This large, population-based study of umbilical cord gas and lactate levels in an unselected population, stratified by delivery mode, represents a previously unavailable benchmark for the evaluation of umbilical cord gases. Arterial umbilical cord pH values for infants delivered by elective caesarean delivery without labor (median pH 7.28) reflect a lower prelabor fetal pH baseline than previously assumed. This finding, coupled with our determination that a 2 standard deviation below normal pH limit of 7.1, instead of the historic arbitrary pH of 7.2 threshold, helps to explain the poor positive predictive value of electronic fetal heart rate monitoring, a test designed to detect arterial pH levels that have fallen from an assumed baseline near pH 7.4 to an assumed potentially injurious pH level of <7.2. Uncomplicated labor, even when prolonged, does not generally lead to a clinically significant cumulative hypoxic stress to the human fetus. These findings, along with our determination that there is no difference in the acid-base status among infants delivered by cesarean delivery for fetal heart rate concerns, help to explain the failure of current approaches in labor and delivery management to reduce the rates of neonatal hypoxic-ischemic encephalopathy and cerebral palsy, conditions that almost always reflect developmental events rather than the effects of labor on the fetus.

An Update of Our Understanding of Fetal Heart Rate Patterns in Health and Disease

UNDERSTANDING FETAL HEART RATE PATTERNS THAT MAY PREDICT ANTENATAL AND INTRAPARTUM NEURAL INJURY: Christopher A. Lear, Jenny A. Westgate, Austin Ugwumadu, Jan G. Nijhuis, Peter R. Stone, Antoniya Georgieva, Tomoaki Ikeda, Guido Wassink , Laura Bennet , Alistair J. Gunn Seminars in Pediatric Neurology Volume 28, December 2018, Pages 3-16 Electronic fetal heart rate (FHR) monitoring is widely used to assess fetal well-being throughout pregnancy and labor. Both antenatal and intrapartum FHR monitoring are associated with a high negative predictive value and a very poor positive predictive value. This in part reflects the physiological resilience of the healthy fetus and the remarkable effectiveness of fetal adaptations to even severe challenges. In this way, the majority of "abnormal" FHR patterns in fact reflect a fetus' appropriate adaptive responses to adverse in utero conditions. Understanding the physiology of these adaptations, how they are reflected in the FHR trace and in what conditions they can fail is therefore critical to appreciating both the potential uses and limitations of electronic FHR monitoring.

INDUCTION OF LABOR AND ITS FETOMATERNAL OUTCOME

Induction of labor is opted for benefits of expeditious delivery to outweigh the risks of continuing the pregnancy. Aims and Objectives: To study the indications and methods of induction of labor &amp; to correlate Feto-Maternal outcome. Materials &amp; Methods: The present study was conducted on 150 pregnant women. It is a prospective observational study, conducted from April 2021 to September 2021. Patient details with Indication, examination, pre-induction Modified Bishops score, Partogram, were noted of 150 pregnant women and the results were analyzed. Electronic fetal heart rate monitoring was done in all except Intra-uterine Fetal Demise (IUFD) cases. Methods used were Dinoprostone, misoprostol, mechanical dilatation using foleys catheter single or in combination with each other. SPSS version 23.0 was used for statistical analysis, statistical significance was set as p&lt;0.05. Result: Common indications for induction were Past-dated pregnancy, followed by Gestational- Hypertensive disorders, Oligoamnios, Pre-labor rupture of membranes respectively. Among the 150 mothers, 113(75.3%) delivered vaginally and 37(24.6%) underwent LSCS. Dinoprostone gel was the dominant method used. Mechanical dilatation with Dinoprostone for induction of labor had a better outcome and less rate of failed induction. 4 mothers in this study were diagnosed with IUFD and induced with Mechanical Dilatation followed by Dinoprostone, all delivered vaginally. NICU admissions were required in 21.7%, 25%, 22% of the mothers who were induced with Dinoprostone, Misoprostol and Mechanical Dilatation respectively. Conclusion: Most common indication for induction is Past dated pregnancy. Most common method used is Dinoprostone alone. Perinatal Morbidity was more with Misoprostol. No maternal and Perinatal mortality.

Baseline/acceleration/deceleration determination of fetal heart rate signals using a novel ensemble LCResU-Net

ObjectiveAccording to guidelines on electronic fetal heart rate (FHR) monitoring, visual FHR interpretation by obstetricians depends on the recognition of patterns (mainly including baseline, accelerations and decelerations (A/D)). Computer-assisted FHR analysis can effectively reduce obstetricians' inconsistency and improve fetal diagnosis efficiency. Precisely detecting patterns is one of the primary challenges of current computer-aided analysis. This study aims to propose an ensemble U-Net (augmented with residual, layer, and channel shortcut connections) (ELCResU-Net) with minimal post-processing to address the problem. MethodsIn this study, A/D are firstly detected with the proposed ELCResU-Net in the FHR signal. After removing detected A/D, this signal is filtered using a progressive trimming procedure based on long-term and short-term frames that consider the continuity and stability of the baseline. Finally, the remaining signal is used to compute the baseline, and thereby A/D of FHR signals are determined. The proposed ELCResU-Net is composed of four LCResU-Nets with kernel sizes of 21, 31, 61 and 81, respectively. The LCResU-Net architecture consists of an encoder block and a corresponding decoder block followed by a point-wise classification layer to construct the 1D segmentation map of A/D from the input FHR signal. In the novel LCRes block of ELCResU-Net, three shortcut connections are used to dynamically prune unimportant channel/layer/block to improve the determination performance. ResultsThe proposed model is trained on the open-access training data set of the Catholic University of Lille France (CULF-DB) and then tested on its test data set and the independent database of the Jinan University (JNU-DB). Experimental results demonstrate that the proposed method achieves the accelerations’ F1-score of 78.82 %, the decelerations’ F1-score of 79.10 %, the baseline difference of 2.61 bpm, the synthetic inconsistency coefficient of 49.99 % and the morphological analysis discordance index of 3.89 % in CULF-DB, which are the best performance ever achieved. On the JNU-DB dataset, the performance of the proposed method is also superior to most competing algorithms. ConclusionThe proposed ELCResU-Net for baseline/A/D determination of FHR signals achieves a high level of performance in morphological analysis.

Fetal heart rate tracings associated with eclamptic seizures

Although there is a well-known association between fetal bradycardia and maternal eclampsia, the characteristics of fetal heart rate tracings after an eclamptic seizure have not previously been thoroughly described. Fetal heart rate changes are thought to be related to maternal lactic acidemia caused by vasospasm and uterine hyperactivity leading to placental hypoperfusion and fetal hypoxia. The decision to intervene in the case of an abnormal fetal heart rate tracing after an eclamptic seizure is often difficult; however, maternal resuscitation should be the primary focus. This study aimed to quantify and characterize fetal heart rate changes associated with a maternal eclamptic seizure. Moreover, we sought to document subsequent obstetrical management following these seizures complicated by fetal heart rate decelerations. This was a retrospective study of fetal heart rate tracings associated with eclampsia during a 13-year period at a single institution. Eclampsia was diagnosed following the 2013 Executive Summary of the American College of Obstetricians and Gynecologists criteria. Tracings were independently reviewed and classified by 3 physicians using the National Institute of Child Health and Human Development Criteria. Hospital records were reviewed to ascertain obstetrical management after the eclamptic seizure. A total of 107 women were diagnosed with eclampsia from January 2009 to December 2021. Of these women, 31 experienced 34 intrapartum seizures during which time electronic fetal heart rate monitoring was ongoing. During the 34 seizures, fetal heart rate decelerations were documented in 79% of cases. The mean duration of bradycardia was 5.80±2.98 minutes with a range of 2 to 15 minutes. Fetal heart decelerations occurred, on average, 2.7±1.6 minutes after the onset of the eclamptic seizure. In half of the fetuses with fetal heart rate changes, fetal tachycardia followed, and in 48% of cases, there was minimal variability noted. As a result of the fetal heart rate tracings and clinical findings, 4 women underwent an emergent cesarean delivery, including 2 that were diagnosed with placental abruption. In this cohort, there were 4 cases of abruption. The mean duration from the seizure to delivery was 299±353 minutes. The mean neonatal cord pH was 7.20±0.11 with a mean base excess of-8.6±4.4 mmol/L. There was no perinatal death. After an eclamptic seizure, 79% of fetuses demonstrated prolonged decelerations, and half of the fetuses developed fetal tachycardia after recovery from the episode of bradycardia. Despite these periods of fetal heart rate decelerations associated with eclampsia, prioritization of maternal support and stabilization resulted in a favorable perinatal outcome without immediate operative intervention in more than two-thirds of cases.

Category II Intrapartum Fetal Heart Rate Patterns Unassociated With Recognized Sentinel Events: Castles in the Air.

The evolution of continuous electronic fetal heart rate (FHR) monitoring has presented the obstetrician with a critical clinical conundrum: basic science observations suggest that such monitoring might be associated with improved long-term neurologic outcomes, yet, after a half century of use and millions of cesarean deliveries based on FHR monitoring, evidence for such improvement remains absent. This dichotomy appears to be related to widespread misconceptions regarding the physiology underlying various FHR patterns and the developmental origins of cerebral palsy. These misconceptions are strengthened by a reliance on anecdotal experience and tradition in lieu of evidence-based medicine, the confusing "category II" FHR designation, medical-legal considerations, and our tendency to view fetal monitoring, as originally conceptualized, as a single, indivisible entity whose concepts must be accepted or rejected en bloc. Ill-defined and largely imaginary conditions such as "depletion of fetal reserve" are particularly harmful and their use in clinical medicine uniquely not evidence based. A solution to this self-inflicted injury to our specialty will require a concerted effort involving teachers, authors, and researchers.

Cumulative Deceleration Area: A Simplified Predictor of Metabolic Acidemia

(Abstracted from J Matern Fetal Neonatal Med 2021;34:3104–3111) Electronic fetal heart rate (FHR) monitoring is a mainstay of intrapartum clinical care, despite low agreement on the value of key elements of tracing analysis among obstetricians. The degree of heart rate variability and type of deceleration are used as etiologic indicators of the hypoxic injury driving deceleration but rely on subjective interpretation.

Safety of Internal Electronic Fetal Heart Rate Monitoring During Labor

Abstract Objective: To investigate the safety and efficacy of internal electronic fetal heart rate (FHR) monitoring during labor. Methods: This was a retrospective case-control study, which was an analysis of monitoring FHR with a fetal scalp electrode or a Doppler probe (94 pregnant women per group). In the internal monitoring group, when the opening of the uterine orifice was ≥3 cm, the fetal scalp electrode was placed after natural or artificial rupture of the membrane. FHR was simultaneously monitored using a Doppler probe. In the external monitoring group, continuous FHR monitoring was performed using an ultrasound Doppler transducer fixed on the maternal abdomen. The toco transducer was used to record uterine contractions. Pathological examination of the placenta was performed prospectively in 49 and 48 cases in the internal electronic FHR monitoring group and control group, respectively. Maternal-infant outcomes (e.g. fever, puerperal infection, puerperal morbidity, delivery mode, Apgar score, and scalp injury) were recorded. Umbilical artery blood was extracted for blood gas analysis. Differences between the two groups were compared using the paired t-test, χ 2 test, Yates corrected χ 2 test or Fisher exact test. Results: Non-statistically significant differences between the internal and external monitoring groups were observed in the incidence of neonatal acidosis (1/94 (1.06%) vs. 3/94 (3.19%), respectively; χ 2 = 0.255, P = 0.613), cesarean section/operative vaginal delivery (8/94 (8.51%) vs. 15/94 (15.96%), respectively; χ 2 = 2.427, P = 0.181), fever during labor (18/94 (19.15%) vs. 15/94 (15.96%), respectively; χ 2 = 0.331, P = 0.565), puerperal morbidity (2/94 (2.13%) vs. 3/94 (3.19%), respectively; χ 2 = 0.000, P = 1.000), chorioamnionitis (9/49 (18.37%) vs. 7/48 (14.58%), respectively; χ 2 = 0.252, P = 0.616), and neonatal asphyxia (0/94 (0.00%) vs. 1/94 (1.06%), respectively; χ 2 = 0.000, P = 1.000). There were no puerperal infections, neonatal scalp injuries, or scalp abscesses found in either group. Using the internal monitoring value as reference, the incidence of FHR false deceleration in external FHR monitoring was 20.21% (19/94 women). Conclusion: Internal FHR monitoring during labor does not increase the incidence of adverse perinatal outcomes. External monitoring was associated with FHR false decelerations.

Relationship Between Umbilical Cord Gas Values and Neonatal Outcomes: Implications for Electronic Fetal Heart Rate Monitoring.

Relationship Between Umbilical Cord Gas Values and Neonatal Outcomes: Implications for Electronic Fetal Heart Rate Monitoring.

The Efficacy of In-Phase and Quadrature Demodulation in Electronic Fetal Heart Rate Monitoring During Labor

Abstract Objective: To investigate the efficacy of in-phase and quadrature (IQ) demodulation in electronic fetal heart rate monitoring (EFM) to reduce false reports of fetal heart rate (FHR) doubling or halving. Methods: This is a prospective cohort study. A total of 263 full-term pregnant women who delivered at Peking University Shenzhen Hospital between August 2019 and July 2020 were prospectively enrolled in the study. FHR monitoring began when the cervix was dilated to 2–3 cm and continued until delivery. Raw fetal Doppler audio signals and internal and external cardiotocography curves from internal electrode monitoring, EFM with conventional demodulation (external), and EFM with IQ demodulation (external) were acquired to compare FHR doubling and halving time. In cohort 1, FHR was compared between IQ demodulation and conventional demodulation. In cohort 2, FHR was compared between IQ demodulation, conventional demodulation, and internal FHR monitoring. Count data were statistically analyzed using the Chi-squared test, and measurement data were statistically analyzed using t-test for correlation coefficients, and Bland-Altman analysis for concordance ranges. Results: To compare IQ demodulation and conventional demodulation, 225 pregnant women were monitored for a total of 835,870 seconds. The beat-to-beat interval of FHRs in raw fetal Doppler audio signals was used as the reference. The results showed a doubling time of 3401 seconds (0.407%, 3401/835,870) and a halving time of 2918 seconds (0.349%, 2918/835,870) with conventional demodulation, compared to 241 seconds (0.029%, 241/835,870) and 589 seconds (0.070%, 589/835,870), respectively, with IQ demodulation. IQ demodulation reduced FHR doubling by approximately 93% (3160/3401) and FHR halving by approximately 80% (2329/2918) compared to conventional demodulation (P &lt; 0.01). To compare IQ demodulation, conventional demodulation, and internal FHR monitoring, 38 pregnant women were monitored for a total of 98,561 seconds. FHR from internal electrode monitoring was used as the reference. The results showed a doubling time of 238 seconds (0.241%, 238/98,561) and a halving time of 235 seconds 0.238%, 235/98,561) with conventional demodulation, compared with 30 seconds (0.030%, 30/98,561) and 81 seconds (0.082%, 81/98,561), respectively, with IQ demodulation (P &lt; 0.05). No significant difference was observed in doubling or halving time between IQ demodulation and internal FHR monitoring (P &gt; 0.05). IQ demodulation was more closely correlated with internal FHR monitoring than conventional demodulation (0.986 vs. 0.947). The Bland-Altman analysis showed that the concordance range of IQ demodulation vs. internal FHR monitoring was significantly narrower than that of conventional demodulation vs. internal FHR monitoring ((−5.32,6.01) vs. (−10.87,11.46)). Conclusion: EFM with IQ demodulation significantly reduces false FHR doubling and halving, with an efficacy similar to that of internal FHR monitoring.

FETAL TYPE CLASSIFICATION BASED ON FETAL ELECTROCARDIOGRAPH IN NON-STRESS TESTS

Electronic fetal heart rate (FHR) monitoring is a technical means to evaluate the state of the fetus in the uterus by monitoring FHR. The main purpose is to detect intrauterine hypoxia and take corresponding medical measures timely. Because the fetus sleeps quietly for up to 1 hour sometimes, ultrasound Doppler is not easy to continuously detect for a long time. The electronic fetal monitor obtains the fetal heart rate, which not only improves the accuracy and comfort, but also the convenient implementation of long-term monitoring. It is beneficial to reduce perinatal fetal morbidity and mortality. This study used maternal–fetal Holter monitor which is based on the technology of fetal electrocardiograph (FECG) to collect the FHR, and then design algorithm to extract the baseline FHR, acceleration, variation, sleep-wake cycle and nonlinear parameters. There were significant differences in the 22 parameters between the normal and the suspicious group. Using the 22 characteristic parameters, the support vector machine was used to classify the normal and the suspected group of fetuses. 80% of the data was used to train a classification model. The remaining 20% of the data was used as a test set and its accuracy reached 93.75%.

Erroneous Recording of Maternal Heart Rate as Fetal Heart Rate During Second Stage of Labour: Isn’t it Time to Stop this?

Electronic Fetal Heart Rate (FHR) monitoring is recommended to assess fetal well-being during labour in high risk pregnancies. This Cardiotocograph (CTG) monitoring relies on the ultrasound technology with the limitation of signal loss in 15% to 40% of the cases [1]. In the earlier versions of these CTG monitors, fetal heart tracings were generally of reasonable quality with many artefacts and some degree of occasional large signal noise. Subsequent models were improved by signal modulation and autocorrelation. Although, these new methodologies of signal processing have reduced the signal loss, the issues of inadvertent monitoring of the maternal heart rate as fetal heart rate and inaccurate evaluations of baseline fetal heart rate (i.e. doubling or halving) continue to pose difficulties during intrapartum fetal heart rate monitoring.

1067 Electronic FHR monitoring, pH and newborn outcomes – this is as good as it gets

To examine the relationship between umbilical artery (UA) cord gas values and fetal tolerance of labor and/or delivery. We hypothesized the existence of wide biologic variability in fetal tolerance of metabolic acidemia which, if present, would weaken a fundamental assumption underlying the use of EFHRM. A retrospective cohort study of term, singleton fetuses delivered between 2012 and 2020. Universal cord gases were collected. Umbilical cord gas values and Apgar scores were extracted. We calculated Spearman correlation coefficients (CC) and constructed ROC curves for UA pH and base excess (BE) as predictors of Apgar score. Our cohort included cord gas and Apgar scores from 29,787 deliveries. The statistical correlation between UA pH and BE and both 1 and 5 minute Apgar scores was weak or non-existent in both the group as a whole and in all pH range sub-groups (Table 1). ROC curve analysis of pH as a predictor of 5 minute Apgar >=7 showed only an acceptable discrimination (AUC= 0.75 95%CI 0.71-0.79, p< 0.01)) with a similar story for base excess (AUC=0.745 95%CI 0.708-0.782, p< 0.01). Subgroup analysis of deliveries with pH >7.2 or BE >-4 showed even poorer predictive ability (Figure 1). Of 8 newborns who underwent cooling for HIE, 3 (38%) had UA pH > 7.15. The use of EFHRM is predicated upon a documented correlation between certain FHR patterns and UA pH, and an arbitrary, presumed correlation between pH and fetal tolerance of labor/delivery, as reflected in newborn condition. To the extent that the latter relationship is invalid, the former correlation is irrelevant. Our data demonstrate a weak to absent correlation between metabolic acidemia and even short term fetal condition, confirming wide biologic variability in fetal tolerance of the hypoxic stress of labor and significantly weakening this latter assumption. No amount of future tweaking of FHR pattern interpretation is likely to result in improved newborn outcomes given this flaw in one fundamental assumption upon which FHRM is based.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Characteristics of fetal and maternal heart rate tracings during labor: A prospective observational study.

Fetal well-being is assured during labor and delivery with the employment of electronic fetal heart monitoring (EFHM). In uncommon instances, maternal heart rate (MHR) instead of fetal heart rate (FHR) can be the source of signals on monitors (signal ambiguity) leading to erroneous interpretation and management. Information about MHR characteristics are comparatively inadequate. We aim to analyze and compare MHR and FHR characteristics during the first and second stages of labor. A prospective cohort study was conducted in a single tertiary care center during a one year period. Fifty one healthy full term women with singleton pregnancies during labor were enrolled. Uterine contractions, MHR and FHR were recorded simultaneously during both stages of labor by monitors designed for twin gestation. When compared to FHR, MHR had significantly lower baseline rate during 1st and 2nd stages (p < 0.0001). It demonstrated also more marked beat-to-beat variability during both stages (p < 0.0001). MHR showed significantly more accelerations (p = 0.03 and p = 0.008) and less decelerations (p < 0.0001 and p = 0.021) during 1st and 2nd stages respectively. All characteristic parameters and patterns produced by FHR could be mimicked by MHR as well, though, at different frequencies. Understanding EFHM patterns suspected to be MHR artefacts and the employment of modern monitors that simultaneously obtain and display FHR and MHR can unmask ambiguity and avert related misinterpretation problems. Similar studies should be conducted in high-risk groups where the potential for fetal hypoxia/acidosis is increased.

A Study on Electronic Fetal Heart Rate Monitoring in Fetal Distress and Neonatal Outcome

A Study on Electronic Fetal Heart Rate Monitoring in Fetal Distress and Neonatal Outcome

Edward H. Hon, MD (1917-2006): A scientist, inventor, academician and the pioneer for the development of electronic fetal heart rate monitoring.

To describe the professional life of Edward H. Hon, MD, and the course of his academic career for the development of electronic fetal heart rate (FHR) monitoring. Review of archives at the Loma Linda University related to Dr Hon's early education and medical school training, his postgraduate training at Yale University, his faculty appointments at Yale University, University of Southern California and his research accomplishment related to electronic FHR monitoring. Primarily, Dr Hon advanced the clinical application of the electronic FHR monitoring, particularly during labor and delivery. Dr Hon also defined significance of FHR patterns based on years of clinical studies and astute observations. Currently, electronic FHR monitoring, during pregnancy and labor/delivery, has a universal application. Dr Hon's research contribution on FHR monitoring, and its impact for the welfare of mother and her unborn child, is well recognized.

Continuous electronic fetal heart monitoring versus intermittent auscultation during labor: Would the literature outcomes have the same results if they were interpreted following the NICHHD guidelines?

All guidelines regarding electronic fetal heart monitoring (EFM) before 2008 were designed to avoid more hypoxia than acidosis. In addition, the results of the Cochrane meta-analysis of 2013 do not show a significant improvement in neonatal outcomes using EFM or intermittent auscultation (IA). We retrospectively evaluated the results on delivery outcomes arising from a comparison between EFM and IA during labor of 2 specific and high-quality trials. We hypothesized that revisiting the delivery outcomes through the adoption of the recent National Institute of Child Health and Human Development (NICHHD) guidelines, the reported delivery outcomes would be different. The study retrospectively evaluated the results on delivery outcomes arising from the comparison between EFM and IA during labor of the "Dublin trial" and "Vintzileos trial" published, respectively, in 1985 and 1993. A translational model was constructed to recalculate these results, applying a correction factor to estimate the number of pathological patterns using the NICHHD guidelines for EFM. After the reevaluation of the 2 trials using the proposed correction factor, the comparison of the recalculated cesarean section and operative delivery rates for fetal distress between EFM and IA group were no longer statistically significant, both in the Dublin trial and Vintzileos trial. Even the comparison of the recalculated incidence of the rate of non-reassuring fetal heart rate (FHR) patterns in the EFM and IA groups has not given any indication of significance for the Vintzileos trial. Our results lead to reconsidering the results of the Dublin trial and Vintzileos trial in terms of operational rates of births, hypothesizing that these results would have been significantly lower if FHR traces were interpreted using the current NICHHD guidelines, which aim to identify potential acidotic fetuses rather than hypoxic ones.