Fetal heart rate development during labour.

BACKGROUND: Fresh stillbirths (FSB) and very early neonatal deaths (VEND) are important global challenges with 2.6 million deaths annually. The vast majority of these deaths occur in low- and low-middle income countries. Assessment of the fetal well-being during pregnancy, labour, and birth is normally conducted by monitoring the fetal heart rate (FHR). The heart rate of newborns is reported to increase shortly after birth, but a corresponding trend in how FHR changes just before birth for normal and adverse outcomes has not been studied. In this work, we utilise FHR measurements collected from 3711 labours from a low and low-middle income country to study how the FHR changes towards the end of the labour. The FHR development is also studied in groups defined by the neonatal well-being 24 h after birth. METHODS: A signal pre-processing method was applied to identify and remove time periods in the FHR signal where the signal is less trustworthy. We suggest an analysis framework to study the FHR development using the median FHR of all measured heart rates within a 10-min window. The FHR trend is found for labours with a normal outcome, neonates still admitted for observation and perinatal mortality, i.e. FSB and VEND. Finally, we study how the spread of the FHR changes over time during labour. RESULTS: When studying all labours, there is a drop in median FHR from 134 beats per minute (bpm) to 119 bpm the last 150 min before birth. The change in FHR was significant ([Formula: see text]) using Wilcoxon signed-rank test. A drop in median FHR as well as an increased spread in FHR is observed for all defined outcome groups in the same interval. CONCLUSION: A significant drop in FHR the last 150 min before birth is seen for all neonates with a normal outcome or still admitted to the NCU at 24 h after birth. The observed earlier and larger drop in the perinatal mortality group may indicate that they struggle to endure the physical strain of labour, and that an earlier intervention could potentially save lives. Due to the low amount of data in the perinatal mortality group, a larger dataset is required to validate the drop for this group.

Knowledge on intrapartum care practices among skilled birth attendants in Cambodia-a cross-sectional study.

BACKGROUND: Delivery is a critical moment for pregnant women and babies, and careful monitoring is essential throughout the delivery process. The partograph is a useful tool for monitoring and assessing labour progress as well as maternal and foetal conditions; however, it is often used inaccurately or inappropriately. A gap between practices and evidence-based guidelines has been reported in Cambodia, perhaps due to a lack of evidence-based knowledge in maternity care. This study aims to address to what extent skilled birth attendants in the first-line health services in Cambodia have knowledge on the management of normal delivery, and what factors are associated with their level of knowledge. METHODS: Midwives and nurses were recruited working in maternity in first-line public health facilities in Phnom Penh municipality, Kampong Cham and Svay Rieng provinces. Two self-administered questionnaires were applied. The first consisted of three sections with questions on monitoring aspects of the partograph: progress of labour, foetal, and maternal conditions. The second consisted of questions on diagnostic criteria, normal ranges, and standard intervals of monitoring during labour. A multiple linear regression analysis was performed to identify relationships between characteristics of the participants and the questionnaire scores. RESULTS: Of 542 eligible midwives and nurses, 523 (96%) participated. The overall mean score was 58%. Only 3% got scores of more than 90%. Multivariate analysis revealed that 'Kampong Cham province', 'younger age', and 'higher qualification' were significantly associated with higher scores. Previous training experience was not associated with the score. Substantial proportions of misclassification of monitoring items during labour were found; for example, 61% answered uterine contraction as a foetal condition, and 44% answered foetal head descent and 26% answered foetal heart rate as a maternal condition. CONCLUSION: This study found that knowledge was low on delivery management among skilled birth attendants. Previous training experience did not influence the knowledge level. A lack of understanding of physiology and anatomy was implied. Further experimental approaches should be attempted to improve the knowledge and quality of maternity services in Cambodia.

Pregnancy and childbirth are natural phenomena, but sometimes have risk for mothers and babies. Therefore, childbirth should be carefully and continuously monitored by the health care professional. The 'partograph' is a useful tool that defines three monitoring aspects of the delivery progress, and conditions of the mother and intrauterine baby. However, it is often used inaccurately or inappropriately in low- and middle-income countries. We hypothesised that health professionals who assist childbirth cannot effectively monitor delivery conditions because their knowledge is insufficient. Therefore, we evaluated the knowledge on monitoring the process of childbirth and explored factors which affect the level of knowledge among health care providers in Cambodia.Midwives and nurses were targeted in this study who deal with normal deliveries in the capital city and two provinces. The questionnaire was designed to evaluate if their knowledge on three monitoring aspects is accurate.Of 542 eligible personnel, 523 (96%) participated. The mean score was 58%. Only 3% got scores of more than 90%. According to the statistical analysis, 'working in Kampong Cham province', 'younger age', and 'higher qualification' were significantly associated with higher scores. Previous training experience was not associated with the score.This study found that basic knowledge was low on delivery management among health care providers. We suspect that a deficiency of basic medical knowledge, such as physiology and anatomy, causes the lack of knowledge on the childbirth process. Further intervention should be attempted to improve the knowledge and quality of maternity services in Cambodia.

Relative accuracy of computerized intrapartum fetal heart rate pattern recognition by ultrasound and abdominal electrocardiogram detection.

INTRODUCTION: Noninvasive fetal heart rate monitoring using transabdominal fetal electrocardiographic detection is now commercially available and has been demonstrated to be an effective alternative to traditional Doppler ultrasonographic techniques. Our objective in this study was to compare the results of computerized identification of fetal heart rate patterns generated by ultrasound-based and transabdominal fetal electrocardiogram-based techniques with simultaneously obtained fetal scalp electrode-derived heart rate information. MATERIAL AND METHODS: We applied an objective computer-based analysis for recognition of fetal heart rate patterns (Monica Decision Support) to data obtained simultaneously from a direct fetal scalp electrode, Doppler ultrasound, and the abdominal-fetal electrocardiogram techniques. This allowed us to compare over 145 hours of fetal heart rate patterns generated by the external devices with those derived from the scalp electrode in 30 term singleton uncomplicated pregnancies during labor. The direct fetal scalp electrode is considered to be the most accurate and reliable technique used in current clinical practice, and was, therefore, used as the standard for comparison. The program quantified the baseline heart rate, long- and short-term variability. It indicated when an acceleration or deceleration was present and whether it was large or small. RESULTS: Ultrasound was associated with significantly greater deviations from the fetal scalp electrode results than the abdominal fetal electrocardiogram technique in recognizing the correct baseline heart rate, its variability, and the presence of small and large accelerations and small decelerations. For large decelerations the two external methods were each not significantly different from the scalp electrode results. CONCLUSIONS: Noninvasive fetal heart rate monitoring using maternal abdominal wall electrodes to detect fetal cardiac activity more reliably reproduced the computerized analysis of heart rate patterns derived from a direct fetal scalp electrode than did traditional ultrasound-based monitoring. Abdominal-fetal electrocardiogram should, therefore, be considered a primary option for externally monitored patients.

A new microdialysis probe for continuous lactate measurement during fetal monitoring: Proof of concept in an animal model.

INTRODUCTION: Cardiotocography (CTG) is currently the most commonly used method for intrapartum fetal monitoring during labor. However, a high false-positive rate of fetal acidosis indicated by CTG leads to an increase in obstetric interventions. We developed a microdialysis probe that is integrated into a fetal scalp electrode allowing continuous measurement of lactate subcutaneously, thus giving instant information about the oxygenation status of the fetus. Our aim was to establish proof of concept in an animal model using a microdialysis probe to monitor lactate subcutaneously. MATERIAL AND METHODS: We performed an in vivo study in adult male wild-type Wistar rats. We modified electrodes used for CTG monitoring in human fetuses to incorporate a microdialysis membrane. Optimum flow rates for microdialysis were determined in vitro. For the in vivo experiment, a microdialysis probe was inserted into the skin on the back of the animal. De-oxygenation and acidosis were induced by lowering the inspiratory oxygen pressure. Oxygenation and heart rate were monitored. A jugular vein cannula was inserted to draw blood samples for analysis of lactate, pH, pco2 , and saturation. Lactate levels in dialysate were compared with plasma lactate levels. RESULTS: Baseline blood lactate levels were around 1 mmol/L. Upon de-oxygenation, oxygen saturation fell to below 40% for 1 h and blood lactate levels increased 2.5-fold. Correlation of dialysate lactate levels with plasma lactate levels was 0.89 resulting in an R2 of .78 in the corresponding linear regression. CONCLUSIONS: In this animal model, lactate levels in subcutaneous fluid collected by microdialysis closely reflected blood lactate levels upon transient de-oxygenation, indicating that our device is suitable for subcutaneous measurement of lactate. Microdialysis probe technology allows the measurement of multiple compounds in the dialysate, such as glucose, albumin, or inflammatory mediators, so this technique may offer the unique possibility to shed light on fetal physiology during the intrapartum period.

A Fetal ECG Monitoring System Based on the Android Smartphone.

In this paper, a fetal electrocardiogram (ECG) monitoring system based on the Android smartphone was proposed. We designed a portable low-power fetal ECG collector, which collected maternal abdominal ECG signals in real time. The ECG data were sent to a smartphone client via Bluetooth. Smartphone app software was developed based on the Android system. The app integrated the fast fixed-point algorithm for independent component analysis (FastICA) and the sample entropy algorithm, for the sake of real-time extraction of fetal ECG signals from the maternal abdominal ECG signals. The fetal heart rate was computed using the extracted fetal ECG signals. Experimental results showed that the FastICA algorithm can extract a clear fetal ECG, and the sample entropy can correctly determine the channel where the fetal ECG is located. The proposed fetal ECG monitoring system may be feasible for non-invasive, real-time monitoring of fetal ECGs.

Is portable foetal electrocardiogram monitor feasible for foetal heart rate monitoring of small for gestational age foetuses in the home environment.

Small-for-gestational-age (SGA) foetuses are at greater risk of complications than normal foetuses. Studies have demonstrated that foetal electrocardiogram (ECG) device (Monica-AN24) can be employed for monitoring foetal heart rate (FHR). However, its reliability and acceptability has not been assessed in SGA foetuses. This study was aimed at: (a) determining the acceptability of wearing the device more than once, (b) investigating the reliability of acquiring successful FHR data at different gestation. Patients with singleton non-anomalous foetus >24 weeks gestation and an estimated foetal weight below tenth percentile were recruited. Thirty-five women wore the device once. Twenty-four of these wore second time (68.6%). Overall, success-rate of FHR signals was 48.6% and increased to 68.8% beyond 34 weeks gestation. Foetal ECG is a promising method for monitoring SGA foetus >34 weeks gestation. Compared to day recordings, foetal signals were more reliable at night. Further studies are required before its clinical utility can be ascertained. IMPACT STATEMENT What is already known on this subject? Pregnancies that are affected by small-for-gestational-age (SGA) foetus pose a major public health problem and are associated with increased perinatal morbidity and mortality. There is no consensus on the optimal timing of delivery. Current methods employed for monitoring SGA foetuses include ultrasound scans for foetal-biometry and Doppler assessments. However, they provide a snapshot of information on foetal well-being, restrict patient mobility and cannot be employed over long-time periods. It is plausible that ambulatory foetal-ECG device that enable monitoring over a longer time period may better inform decisions about the timing of delivery. What do the results of this study add? Trans-abdominal foetal-ECG is a promising method of monitoring SGA foetus in the home setting with a success rate of acquiring reliable foetal heart rate (FHR) data over 90% at night time. What are the implications of these findings for clinical practice and/or further research? Overall, the study approved the concept of long-term home monitoring and has highlighted the facilitators and barriers to wearing the monitor in clinical care. These observations can be used to undertake robust research to assess the use of foetal-ECG monitor singly or in conjunction with current monitoring techniques for optimal foetal surveillance.

[Anti-disturbance Fetal Heart Rate System Based on Combined Maternal-fetal Monitoring].

The existing fetal monitor is prone to false detection in the case of high maternal interference in the second stage of labor. With this background, the article designs and implements a combined maternal-fetal fetal heart monitoring system. The system obtains the Doppler signal of the abdominal fetal heart and the blood oxygen signal of the mother's finger, and estimates the maternal interference degree in the fetal heart rate Doppler signal according to the maximum correlation value between the maternal finger blood oxygen signal and the abdominal fetal heart Doppler signal, and switches the fetal heart rate extraction algorithm between the autocorrelation method suitable for lower interference and improved template method suitable for higher interference according to the maternal interference degree. The accuracy of our method is 9.2% which is higher than that of the improved template matching method and 6.1% higher than that of the autocorrelation method.

Sensors for Fetal Hypoxia and Metabolic Acidosis: A Review.

This article reviews existing clinical practices and sensor research undertaken to monitor fetal well-being during labour. Current clinical practices that include fetal heart rate monitoring and fetal scalp blood sampling are shown to be either inadequate or time-consuming. Monitoring of lactate in blood is identified as a potential alternative for intrapartum fetal monitoring due to its ability to distinguish between different types of acidosis. A literature review from a medical and technical perspective is presented to identify the current advancements in the field of lactate sensors for this application. It is concluded that a less invasive and a more continuous monitoring device is required to fulfill the clinical needs of intrapartum fetal monitoring. Potential specifications for such a system are also presented in this paper.

Development of a Smart Mobile Data Module for Fetal Monitoring in E-Healthcare.

The fetal heart rate (FHR) is a marker of fetal well-being in utero (when monitoring maternal and/or fetal pathologies) and during labor. Here, we developed a smart mobile data module for the remote acquisition and transmission (via a Wi-Fi or 4G connection) of FHR recordings, together with a web-based viewer for displaying the FHR datasets on a computer, smartphone or tablet. In order to define the features required by users, we modelled the fetal monitoring procedure (in home and hospital settings) via semi-structured interviews with midwives and obstetricians. Using this information, we developed a mobile data transfer module based on a Raspberry Pi. When connected to a standalone fetal monitor, the module acquires the FHR signal and sends it (via a Wi-Fi or a 3G/4G mobile internet connection) to a secure server within our hospital information system. The archived, digitized signal data are linked to the patient's electronic medical records. An HTML5/JavaScript web viewer converts the digitized FHR data into easily readable and interpretable graphs for viewing on a computer (running Windows, Linux or MacOS) or a mobile device (running Android, iOS or Windows Phone OS). The data can be viewed in real time or offline. The application includes tools required for correct interpretation of the data (signal loss calculation, scale adjustment, and precise measurements of the signal's characteristics). We performed a proof-of-concept case study of the transmission, reception and visualization of FHR data for a pregnant woman at 30 weeks of amenorrhea. She was hospitalized in the pregnancy assessment unit and FHR data were acquired three times a day with a Philips Avalon® FM30 fetal monitor. The prototype (Raspberry Pi) was connected to the fetal monitor's RS232 port. The emission and reception of prerecorded signals were tested and the web server correctly received the signals, and the FHR recording was visualized in real time on a computer, a tablet and smartphones (running Android and iOS) via the web viewer. This process did not perturb the hospital's computer network. There was no data delay or loss during a 60-min test. The web viewer was tested successfully in the various usage situations. The system was as user-friendly as expected, and enabled rapid, secure archiving. We have developed a system for the acquisition, transmission, recording and visualization of RCF data. Healthcare professionals can view the FHR data remotely on their computer, tablet or smartphone. Integration of FHR data into a hospital information system enables optimal, secure, long-term data archiving.

Clinical evaluation of Statstrip® Lactate for use in fetal scalp blood sampling.

INTRODUCTION: Point-of-care testing of fetal scalp blood lactate is used as an alternative to pH analysis in fetal scalp blood sampling (FBS) during labor. Lactate measurements are not standardized and values vary with each device used. The aim of this study was to evaluate StatStrip® Lactate (SSL) in the clinical setting in comparison with lactate (RLL) and pH (RLpH) using RapidLab® . MATERIAL AND METHODS: We obtained 323 FBS samples from 139 women. Parallel sampling of SSL and RLL/RLpH was performed in 247 samples. Outcome measures were the agreement and discrepancy rates between SSL, RLL and RLpH and the failure rate of all three methods. We constructed a Bland-Altman graph to assess the variability between the measurements across the range of values. The discrepancy rates between methods were compared using previously established cut-off values for SSL indicating reassurance (<5.7 mmol/L) and immediate delivery (>7.0 mmol/L) with those for RLpH (<7.20 and >7.25). RESULTS: SSL showed excellent agreement with RLL (R2 = 0.742) and poor agreement with RLpH (R2 = 0.204). Failure rates for SSL, RLL and RLpH were 7, 43 and 23%, respectively. Using the cut-off values for reassurance and immediate delivery, the discrepancy rates between SSL and RLpH were 14 and 5%, respectively. CONCLUSIONS: SSL is a reliable test to measure lactate in FBS with a low failure rate. As there are discrepancies between SSL and RLpH, and the cut-off values have not yet been evaluated prospectively regarding intervention rates and neonatal outcome, we recommend using SSL in addition to pH in FBS.

Reference values for Lactate Pro 2™ in fetal blood sampling during labor: a cross-sectional study.

OBJECTIVE: Lactate Pro™ (LP1) is the only lactate meter evaluated for fetal scalp blood sampling (FBS) in intrapartum use. The reference values for this meter are: normal value <4.2 mmol/L, preacidemia 4.2-4.8 mmol/L, and acidemia >4.8 mmol/L. The production of this meter has been discontinued. An updated version, Lactate Pro 2TM (LP2), has been launched and is shown to be differently calibrated. The aims of the study were to retrieve a conversion equation to convert lactate values in FBS measured with LP2 to an estimated value if using LP1 and to define reference values for clinical management when using LP2. STUDY DESIGN: A cross-sectional study was conducted at a university hospital in Sweden. A total of 113 laboring women with fetal heart rate abnormalities on cardiotocography (CTG) had FBS carried out. Lactate concentration was measured bedside with both LP1 and LP2 from the same blood sample capillary. A linear regression model was constructed to retrieve a conversion equation to convert LP2 values to LP1 values. RESULTS: LP2 measured higher values than LP1 in all analyses. We found that 4.2 mmol/L with LP1 corresponded to 6.4 mmol/L with LP2. Likewise, 4.8 mmol/L with LP1 corresponded to 7.3 mmol/L with LP2. The correlation between the analyses was excellent (Spearman's rank correlation, r=0.97). CONCLUSION: We recommend the following guidelines when interpreting lactate concentration in FBS with LP2: <6.4 mmol/L to be interpreted as normal, 6.4-7.3 mmol/L as preacidemia indicating a follow-up FBS within 20-30 min, and >7.3 mmol/L as acidemia indicating intervention.

Examiner's finger-mounted fetal tissue oximetry: a preliminary report on 30 cases.

OBJECTIVE: To describe preliminary experience with a finger-mounted fetal tissue oximetry probe during the 2nd stage of labor. MATERIALS AND METHODS: A total of 30 term pregnant women without pregnancy complications were recruited. We measured fetal tissue oxygen saturation (FtO2) by using a finger-mounted fetal tissue oximetry during cervical examinations in the 2nd stage of labor. The data capturing rate of FtO2 and the interclass correlation coefficient were also examined. The mean FtO2 was compared to the neonatal condition assessed by the levels of umbilical cord blood. RESULTS: FtO2 was obtained in all cases, regardless of wetness, hair color, the part of the fetal head that was exposed, rotation of the fetus, color of amniotic fluid, and caput succedaneum. The mean FtO2 was 65.5%±8.58% in normal neonates [Apgar score >7 (1 min), n=25]. The mean FtO2 was significantly correlated with umbilical cord arterial pH (r=0.52, P=0.0030, n=30), but not with umbilical cord arterial partial pressure of oxygen. The interclass correlation coefficient was 0.94. CONCLUSIONS: Tissue oxygen saturation of the fetal head was obtained easily by the examiner's finger-mounted fetal tissue oximetry.

Invention of ultrasonic Doppler fetal actocardiograph and continuous recording of fetal movements.

AIMS: To enable scientific studies on fetal movements and its relation to fetal heart rate directly detecting fetal chest motion with ultrasonic Doppler method. METHODS: A prototype of an ultrasonic Doppler fetal actocardiograph (ACG) was designed and handmade by the author. A 2 MHz ultrasound fetal heart rate (FHR) monitor was remodeled to detect fetal heartbeat and chest movement Doppler signals with a single ultrasound probe. The fetal movement Doppler signal was 20-50 Hz using 2 MHz ultrasound, separated from the fetal heartbeat Doppler signal, which was 100 or more Hz and sent to the autocorrelation FHR meter to record FHR curve, while fetal movement Doppler signals were detected through 20-80 Hz band-pass filter, and changed to spikes recorded on a cardiotocography chart. RESULTS: The spike amplitudes of a moving steel ball expressed fetal movement on the ACG. FHR acceleration synchronized with fetal movement bursts. Fetal resting and active states are separated using the ACG. Fetal hiccupping movements on ACG were regular continuous spikes with 2-3 s intervals. CONCLUSION: Fetal movements and hiccups were correctly recorded with the FHR curve. The relation of FHR and movement will be further clarified in future ACG readings.

Midwives matter more than monitors.

In this column, Sara Wickham takes a sideways look at issues relevant to midwives, students, women and families, inviting us to sit down with a cup of tea and ponder what we think we know. Research has consistently failed to show that electronic fetal monitoring makes a positive difference to women or babies. Yet this technology continues to be used, with some units now using central monitoring systems. This article considers the results of a study showing the effect of these on women's experiences, comparing the value of monitors and midwives.

Validation of a point-of-care (POC) lactate testing device for fetal scalp blood sampling during labor: clinical considerations, practicalities and realities.

BACKGROUND: Although fetal blood sampling for pH is well established the use of lactate has not been widely adopted. This study validated the performance and utility of a handheld point-of-care (POC) lactate device in comparison with the lactate and pH values obtained by the ABL 800 blood gas analyzer. METHODS: The clinical performance and influences on accuracy and decision-making criteria were assessed with freshly taken fetal blood scalp samples (n=57) and umbilical cord samples (n=310). Bland-Altman plot was used for data plotting and analyzing the agreement between the two measurement devices and correlation coefficients (R²) were determined using Passing-Bablok regression analysis. RESULTS: Sample processing errors were much lower in the testing device (22.8% vs. 0.5%). Following a preclinical assessment and calibration offset alignment (0.5 mmol/L) the test POC device showed good correlation with the reference method for lactate FBS (R²=0.977, p<0.0001, 95% CI 0.9 59-0.988), arterial cord blood (R²=0.976, p<0.0001, 95% CI 0.967-0.983) and venous cord blood (R²=0.977, p<0.0001, 95% CI 0.968-0.984). CONCLUSIONS: A POC device which allows for a calibration adjustment to be made following preclinical testing can provide results that will correlate closely to an incumbent lactate method such as a blood gas analyzer. The use of a POC lactate device can address the impracticality and reality of pH sample collection and testing failures experienced in day to day clinical practice. For the StatStrip Lactate meter we suggest using a lactate cut-off of 5.1 mmol/L for predicting fetal acidosis (pH<7.20).