Fetal Heart Rate Tracings Research Articles

1086: Retrospective application of the clark algorithm to cesarean sections for fetal intolerance to labor

Abnormal fetal heart rate tracings account for a significant number of cesarean sections (23% in 2016). Clark, et al. developed an algorithm for management of category II fetal heart rate tracings in labor (figure 1). We aim to determine the extent of compliance and noncompliance of fetal monitoring with the Clark algorithm and if differences lead to disparate neonatal outcomes. This is a retrospective observational study from the resident service at an academic-community tertiary care center from 2013-2018. We reviewed archived fetal heart rate tracings from patients with cesarean section (CS) performed for fetal intolerance to labor (FIL) and interpreted tracings against the algorithm. We assigned tracings to one of three categories: Group 1—compliant; Group 2—noncompliant too early (algorithm permits the patient to labor longer); Group 3—noncompliant too late (algorithm suggests performing the CS sooner). Maternal demographics, features of labor, and neonatal outcomes were compared among the compliant and noncompliant groups. Of the 110 cases, 27 (24.5%) had a CS called in group 1, 49 (44.5%) in group 2, and 34 (30.9%) in group 3. Baseline characteristics were similar. Of the 49 in group 2, 46 (93.9%) violated the algorithm at the same branchpoint (#6, figure 1). In group 3, cesarean sections would have been performed on average 244 minutes earlier had the algorithm been used. Neonatal outcomes were not significantly different among the groups (table 1), including 5-minute Apgar < 7 (2/27 for group 1, 2/49 for group 2, 1/34 for group 3; p=0.71), pH < 7.1 (3/27 for group 1, 4/49 for group 2, 5/34 for group 3; p=0.69), and NICU admit (13/27 for group 1, 26/49 for group 2, 17/34 for group 3; p=0.88). Our retrospective application of the algorithm showed that 44.5% of patients who have CS for FIL may be able to labor longer and that violation at a common decision point on the algorithm is responsible for nearly all such CS. More studies are needed to evaluate if CS rates for FIL can be reduced without impacting neonatal outcomes using the algorithm.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

210: A comparison of misoprostol to dinoprostone vaginal insert for cervical ripening in labor induction

To evaluate time to active labor in parturients who delivered at an academic health system in northeast Ohio before and after implementation of switch in preferred cervical ripening agent from dinoprostone (PGE2) to misoprostol (PGE1). In November 2016, our institute implemented a change from dinoprostone to misoprostol after reviewing cost analysis. This retrospective cohort study represents parturients who delivered before and after implementation. 90 patients were selected for each arm to achieve 80% power. Women were included if they had a term singleton gestation, category I fetal heart rate (FHR) and ≤4 contractions in 10 minute period at time of induction, cephalic presentation, Bishop score ≤6, and age ≥18. Per hospital protocol, dinoprostone was administered 10 mg every 12 hours and misoprostol 25 mcg every 4 hours. Primary outcome was time to active labor (≥6 cm cervical dilation). Time to active labor was selected as this represents the optimal comparison to parturients presenting in spontaneous labor. Secondary outcomes included proportion reaching active labor, time to delivery, delivery type, reason for cesarean, FHR category, tachysystole, chorioamnionitis, and length of hospital stay. 180 patients were included with 90 patients in each group. Time to active labor was 20.9 ± 9.7 hours for dinoprostone and 20.7 ± 10 hours for misoprostol (p = 0.42). FHR category varied between groups with category I tracings throughout labor course in 2.2% of patients in the dinoprostone group versus 10% of patients in the misoprostol group (p = 0.029). 24.4% obtained cesarean delivery with dinoprostone and 25.6% with misoprostol (p = 0.65). Our study showed no statistically significant difference in time to active labor, proportion achieving active labor, cesarean delivery rate, tachysystole, chorioamnionitis, time to delivery, or length of hospital stay in patients receiving dinoprostone compared to misoprostol. More patients had category I FHR tracing throughout entire labor course after receiving misoprostol.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

897: Maternal pulse oximetry to prevent misidentification of fetal heart rate in labor: A cost-effectiveness analysis

Up to 8% of fetal heart rate tracings represent the maternal rather than the fetal heart rate during the second stage of labor. Fetal heart rate patterns can alert clinicians states of fetal distress including hypoxia or asphyxia. The purpose of this study was to determine whether routinely monitoring maternal heart rate during the second stage of labor via pulse oximetry is cost effective. A decision-analytic model was created using TreeAge software to evaluate outcomes of monitoring maternal heart rate in all laboring women during the second stage of labor via pulse oximetry in addition to monitoring fetal heart rate with cardiotocography (CTG) compared to monitoring fetal heart rate alone. Outcomes included cesarean section, neonatal seizures, neonatal death, global developmental delay and cerebral palsy. Probabilities, costs, and utilities were obtained from the literature, and a willingness-to-pay (WTP) threshold was set at $100,000 per quality-adjusted life year (QALY). Analysis accounted for the maternal and neonatal perspective. Sensitivity analyses were performed to determine the robustness of the results. In a theoretical cohort of 2.8 million pregnancies, monitoring the maternal heart rate via pulse oximetry in the second stage results in 11,760 fewer neonatal seizures, 40 fewer cases of cerebral palsy, 191 fewer cases of global developmental delay and 24 fewer neonatal deaths, despite an increase in c-sections. Our model demonstrated that adding maternal pulse oximetry for routine monitoring led to higher QALYs and decreased overall cost (a dominant strategy) compared to external CTG alone. Univariate sensitivity analysis showed that the model was no longer cost-effective when the cost of pulse oximetry exceeded $840 (Figure 1; baseline estimate: $9). Compared to CTG alone, monitoring women in the second stage of labor with maternal pulse oximetry improves outcomes and decreases total costs. Clinicians, quality specialists, and policy makers should consider the impact of monitoring all women with pulse oximeter in the second stage of labor.

914: Second stage of labor: Maternal and perinatal outcomes of cesarean versus attempted operative vaginal delivery

Among women who reach the second stage of labor and require operative delivery, little data exists on the maternal and perinatal outcomes based on attempted operative vaginal delivery (OVD) vs cesarean delivery (CD) without attempted OVD. The objective of this study was to compare the maternal and perinatal outcomes among these two groups. This is a secondary analysis of data from a multicenter prospective study for women enrolled in the Cesarean Registry. We compared the maternal and perinatal outcomes based on whether OVD was attempted or CD was performed without attempt. This study includes singleton, at > 37 weeks, pregnancies that were eligible for OVD (10cm dilated and +2 station). Exclusion criteria included those who underwent CD in second stage with primary indication of non-reassuring fetal heart rate tracing and those with anomalous fetuses. Primary outcome was composite maternal morbidity and secondary outcome was composite neonatal morbidity. A multivariable Poisson regression analysis was used to examine the association between attempt of OVD and outcomes, while adjusting for potential confounding factors that were different between groups at a p value of < 0.1 in univariate analysis. A total of 1,432 women met the inclusion criteria: 1,025 (71%) had an attempted OVD and 407 underwent CD without attempt (39%). Women who attempted OVD were more likely to have composite maternal morbidity (aRR 2.93, 95% CI 1.92-4.49), mostly from third and fourth degree perineal lacerations (Table 1). There was no significant difference in rates of composite neonatal morbidity between groups; however, neonatal birth injury was significantly more frequent in the group who had an attempted OVD (aRR 4.79, 95% CI 1.85-12.42)(Table 2). In women reaching the second stage, CD without attempt was associated with lower maternal morbidity and less neonatal birth injury. Given that OVD training is declining in residency programs, these data may have clinical implications regarding counseling of patients eligible for OVD.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

249: Deceleration area-time ratio as predictor of acidemia in fetuses with early onset growth restriction

There is little existing literature to guide the interpretation of fetal heart rate tracings in growth restricted fetuses with abnormal Doppler studies remote from term. This study sought to determine fetal heart rate parameters associated with fetal acidemia. Data was collected prospectively on 14 pregnancies diagnosed with early-onset intrauterine growth restriction with abnormal umbilical artery Dopplers. All women included in this analysis delivered at less than 32 weeks gestation and had an umbilical artery pH obtained at time of delivery. An investigator blinded to the umbilical cord pH analyzed the last 60 minutes of fetal heart rate tracing prior to delivery and recorded baseline, variability, presence of accelerations, number of decelerations, maximum depth of deceleration, total time spent in deceleration, and total deceleration area (TDA). TDA was defined as area below the fetal baseline in units of 10 beats per 10 seconds. From these data, the ratio of TDA over total deceleration time (TDA/time) was calculated (see Figure 1). Receiver operating characteristic (ROC) curves were used to analyze the ability of each of these parameters to predict umbilical cord pH less than 7.00 and less than 7.10. A p-value < .05 was considered significant. Of the 14 women, 2 had umbilical cord pH values less than 7.00 and 5 with pH less than 7.10. The area under the curve for TDA-time ratio was 1.00 for pH less than 7.00 and .80 for pH less than 7.10. The areas under the curve showed poor predictive value of maximum depth of decelerations, number of decelerations, time spent in deceleration, and TDA (Table 1). A TDA/time cut-off of .15 had a 100% specificity and sensitivity for predicting pH less than 7.0 and a 100% specificity and 40% sensitivity for predicting pH less than 7.10. In this cohort, the TDA/time ratio was the strongest predictor of an abnormal umbilical artery pH, suggesting long, shallow decelerations are of greatest concern in these patients. This represents a novel technique for quantifying these decelerations.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

A before and after study of the impact on obstetric and perinatal outcomes following the introduction of an educational package of fetal heart rate monitoring education coupled with umbilical artery lactate sampling in a low resource setting labor ward in South Africa

IntroductionRates of cesarean section (CS) are increasing and abnormal fetal heart rate tracing and concern about consequent acidosis remain one of the most common indications for primary CS. Umbilical artery (UA) lactate sampling provides clinicians with point of care feedback on CTG interpretation and intrapartum care and may result in altered future practice.Materials and methodsFrom 3rd March - 12th November 2014 we undertook a before and after study in Pretoria, South Africa, to determine the impact of introducing a clinical package of fetal heart rate monitoring education and prompt feedback with UA cord lactate sampling, using a hand-held meter, on maternal and perinatal outcomes.ResultsNine hundred thirty-six consecutive samples were analyzed (pre n = 374 and post n = 562). There was no difference in mean lactate (4.6 mmol/L [95%CI 4.4–4.8] compared with 4.9 mmol/L [95%CI 4.7–5.1], p = 0.089). Suspected fetal compromise was reduced in the post-intervention period: 30·2% vs 22·1%, aOR 0·71, 95% CI 0·52–0·96, p = 0·027. Cesarean section rates were significantly reduced in the univariate analysis: pre- 40·3% vs post-intervention 31·6% (p = 0·007). This reduction remained significant when adjusted for previous cesarean section, primiparity, maternal HIV infection and preterm birth (aOR 0·72, 95%CI 0·54–0·98, p = 0·035). Neonatal outcomes did not differ between the two groups.ConclusionThe introduction of a clinical practice package of fetal heart rate monitoring education combined with routine UA cord lactate sampling has the potential to reduce the cesarean section rate without increasing adverse neonatal outcomes in a low-resource setting.

Cumulative deceleration area: a simplified predictor of metabolic acidemia

Objective Fetal monitoring, ubiquitous in obstetrics is used to predict and prevent intrapartum fetal injury. Despite decades of education and nomenclature revision, clinicians show low agreement on key elements, including the types of deceleration and hence their presumed etiology. Cumulative deceleration area is not dependent on deceleration type and could potentially mitigate this problem. Although deceleration area has shown promise as a marker of acidemia, no reports have shown how deceleration area evolves in late labor. Advances in computerization allow for direct measurement of deceleration area and standard fetal heart rate (FHR) patterns. The objective of this study was to compare the evolution and discrimination performance of deceleration area and other FHR patterns in late labor in term neonates with metabolic acidemia (MA) and in those with normal cord gases. Methods This retrospective cohort study included women with a term singleton (≥37 weeks) in cephalic presentation with cord gas data and FHR tracings available for analysis. MA included neonates with an umbilical artery base deficit >12 mmol/L (n = 132). Controls included those with normal cord gases (base deficit <8 mmol/L) and a 5-minute Apgar score of >6 (n = 1498). Deceleration area and other FHR patterns were summarized and compared in 30-minute segments over the last five hours. Receiver-operating characteristic curves were constructed and AUCs compared. Results Deceleration area had the highest AUC (0.702, 95% CI 0.655–0.749) and was a superior marker of MA compared to baseline (AUC 0.588, 95% CI 0.530–0.645), baseline variability (AUC 0.611, 95% CI 0.558–0.663), and number of late decelerations (AUC 0.582, 95% CI 0.527–0.637). Conclusion Cumulative deceleration area reduces the necessity to determine deceleration type. In a single number, it objectively quantifies three important aspects of decelerations; frequency, depth and duration and was a superior marker of MA compared to baseline level, baseline variability and number of late decelerations. The acidemia group had higher deceleration area over the last two hours prior to delivery. This result indicates that the cumulative area and persistence of repetitive decelerations is important clinically.

Neonatal and maternal outcomes of pregnancies with a fetal diagnosis of congenital heart disease using a standardized delivery room management protocol.

We sought to determine if fetuses with prenatally diagnosed congenital heart disease (CHD) were more likely to undergo cesarean delivery in the setting of a non-reassuring fetal heart rate tracing (NRFHT) and to determine if those fetuses were more likely to have a fetal acidosis. A retrospective cohort study of neonates prenatally diagnosed with CHD from August 2010 to July 2016. The control group consisted of gestational age matched controls without CHD. Each group consisted of 143 patients. The most common reason for cesarean delivery was a NRFHT (control 31% vs CHD 35%, p = 0.67). Fetal acidosis was a rare outcome occurring in only five controls (3.5%) and 11 cases (7.7%) (p = 0.12). These findings demonstrate that with multidisciplinary care coordination, fetuses with a prenatal diagnosis of CHD have similar cesarean rates, labor and delivery management, and delivery room compromise as healthy fetuses.

Umbilical Cord Practices of Members of the American College of Nurse‐Midwives

IntroductionThe purpose of this survey of American College of Nurse‐Midwives (ACNM) members was to describe umbilical cord practices of US midwives and to explore possible modifying factors. Contrasting this study with the 2000 survey of ACNM members on umbilical cord clamping by Mercer, Nelson, and Skovgaard, we hypothesized that there would be an increase in utilization of delayed cord clamping at birth by current midwives. The benefits of adequate placental transfusion at birth via delaying cord clamping (DCC) has been well described for both preterm and term neonates. Surveys and observations of provider practice across the globe show inconsistent uptake of the evidence‐based practices of DCC and cord milking. This study provides a 17‐year update to the Mercer et al study and gives the opportunity for current assessment of umbilical cord management by members of ACNM.MethodsThis was a cross‐sectional study of 1050 active members of ACNM who had attended women in labor and birth within 3 years of the survey. Participants were selected using non‐probability, purposive sampling with recruitment through serial e‐mails. Umbilical cord practices were assessed, and related factors were examined using Chi‐square tests and multivariate logistic regression models.ResultsThe overall response rate was 20%. Ninety‐two percent of the midwives performed DCC in this study as compared with 67% in the initial survey done in 2000. Over 50% of the midwives considered DCC in the presence of the following situations: shoulder dystocia, meconium‐stained fluid, and vaginal birth for a non‐reassuring fetal heart rate tracing. Twenty‐six percent said they would delay clamping if resuscitation was required. “I don't know” was the most common response when it came to cord management for breech births or when vacuum or forceps were used. Cord milking was used less frequently than DCC.DiscussionMidwifery use of DCC has expanded since 2000. The use of cord milking is variable with concerns about the validity of the practice. For many participants, uncertainty is present regarding cord clamping in complex clinical situations. The study provides important guidance for addressing knowledge deficits and continual improvement in practice.

Implementation of the Fetal Monitor Safety Nurse Role: Lessons Learned.

The fetal monitor safety nurse role was created as a supplemental support for nurses assessing fetal heart rate tracings in response to an adverse event. An experienced labor and delivery nurse without a patient care assignment was designated to continuously assess all active fetal monitoring tracings, via an electronic display away from the main nurses' station, as an adjunct to the care and assessment of the nurse with primary responsibility for the patient. The purpose of this project was to evaluate the views of nurses who served as fetal monitor safety nurses about various aspects of the role. Nurses who served as fetal monitor safety nurses were invited to attend a small group session where they completed a survey about the role and then received information on the importance of fetal monitoring safety. Two weeks later, they were asked to take the survey again to evaluate potential changes in viewpoints. Thirty nurses attended small group sessions and completed the survey. Of those, 22 nurses completed the post survey 2 weeks later. There was minimal change in nurses' views of the fetal monitor safety nurse role after attending the small group sessions. Nurses expressed comfort in notifying peers about concerns related to the fetal heart rate tracing and perceived overall safety benefits; however, they felt that safe staffing measures were not in place to support the role. Concerns were expressed about a nurse being in a nondirect patient care position during times of high census and acuity. The fetal monitoring safety nurse may be an innovative potential solution to minimize risk of adverse events during labor that are related to accurate assessment of electronic fetal monitoring data and timely and appropriate interventions. More data are needed on improvements in fetal outcomes and adverse events potentially related to the fetal monitor safety nurse role. Budgetary support and adequate nurse staffing are required to make the role operationally feasible and safe. Valuing and seeking nurses' input as bedside experts about perinatal safety initiatives should be a part of implementing new practices.

An Evaluation of Fetal Heart Rate Characteristics Associated With Neonatal Encephalopathy: A Case-Control Study

(BJOG. 2018;125(11):1480–1487) Neonatal encephalopathy (NE) is characterized by abnormal neurological function that presents with decreased level of consciousness or seizures, difficulty maintaining respirations, and abnormal reflexes or tone. This clinical condition is identified shortly after birth with an incidence of 2 to 6/1000 live births. There is incomplete understanding of the etiology of NE and no evidence-based interventions to prevent its occurrence. The objective of the study was to identify predelivery fetal heart rate (FHR) characteristics associated with NE. The hypothesis was category III FHR tracings would be associated with NE.

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.

Rising Cesarean Rates: Are Primary Sections Overused?

Doubling of C-section rates from year 2000 to 2015 globally was declared an eye-opener on October 13, 2018, in FIGO World Congress. Rapid increase in rates without clear evidence of concomitant decrease in maternal or neonatal morbidity or mortality raises significant concern that cesarean delivery is overused. This review addresses issues related to exponentially rising rates, reasons for it, and strategies to reduce. Previous cesarean delivery has main contribution to rising rates as per evidence from the literature search in last 5years. Focus on optimizing indications of primary C-section resulted in making us rethink modifiable indications like labor dystocia, indeterminate fetal heart rate tracing, suspected fetal macrosomia, malposition, risk-adapted obstetrics, litigation fears, on demand cesarean in literate women and overuse of labor induction. Use of uniform classification system (Robson/WHO classification) with recommendations of WHO, FIGO and annual audits with cloud-based anonymous registry will streamline decisions for cesarean in nullipara and help to control the situation.

Creating a Culture of Excellence Around Fetal Heart Rate Tracings Through Listening and Collaboration

Creating a Culture of Excellence Around Fetal Heart Rate Tracings Through Listening and Collaboration

Use of artificial intelligence (AI) in the interpretation of intrapartum fetal heart rate (FHR) tracings: a systematic review and meta-analysis.

To determine the degree of inter-rater reliability (IRR) between human and artificial intelligence (AI) interpretation of fetal heart rate tracings (FHR), and to determine whether AI-assisted electronic fetal monitoring interpretation improves neonatal outcomes amongst laboring women. We searched Medline, EMBASE, Google Scholar, Scopus, ISI Web of Science and Cochrane database search, as well as PubMed ( www.pubmed.gov ) and RCT registry ( www.clinicaltrials.gov ) until the end of October 2018 to conduct a systematic review and meta-analysis comparing visual and AI interpretation of EFM in labor. Similarly, we sought out all studies evaluating the IRR between AI and expert interpretation of EFM. Weighed mean Cohen's Kappa was calculated to assess the global IRR. Risk of bias was assessed using the Cochrane Handbook for Systematic Reviews of Interventions. We used relative risks (RR) and a random effects (RE) model to calculate weighted estimates. Statistical homogeneity was checked by the χ2 test and I2 using Review Manager 5.3.5 (The Cochrane Collaboration, 2014.) We obtained 201 records, of which 9 met inclusion criteria. Three RCT's were used to compare the neonatal outcomes and 6 cohort studies were used to establish the degree of IRR between both approaches of EFM evaluation. With regards to the neonatal outcomes, a total of 55,064 patients were included in the analysis. Relative to the use of clinical (visual) evaluation of the FHR, the use of AI did not change the incidence rates of neonatal acidosis, cord pH below < 7.20, 5-min APGAR scores < 7, mode of delivery, NICU admission, neonatal seizures, or perinatal death. With regards to the degrees of inter-rater reliability, a weighed mean Cohen's Kappa of 0.49 [0.32-0.66] indicates moderate agreement between expert observers and computerized systems. The use of AI and computer analysis for the interpretation of EFM during labor does not improve neonatal outcomes. Inter-rater reliability between experts and computer systems is moderate at best. Future studies should aim at further elucidating these findings.

Maternal Exercise Uncovers Placental Insufficiency in Diabetic Mothers

Regular physical activity during pregnancy improves or maintains physical fitness, helps with weight management, reduces the risk of gestational diabetes, and enhances patient’s psychological well-being. We studied the possibility to use maternal exercise to test placental reserves in diabetic mothers. We used a motorized treadmill in a moderate exercise regimen (15-minute fast walk at a speed of 3 mph with an incline of 15-25 degrees). Fetal monitoring was provided by using standard Phillips equipment (Avalon CTS and FM40). Adverse fetal outcomes were considered if one or more of the following were present: Category III Fetal Heart Rate (FHR) tracing, 5-minute Apgar score of less than 7, admission to the neonatal intensive care nursery, fetal growth restriction, and fetal and early neonatal death. A total of 819 fetal assessments were performed: 160 patients had gestational diabetes, 80 had pregestational diabetes. The most common complication in fetuses with positive prenatal test results was abnormal FHR in labor (36%) followed by low Apgar score (21%) and need for NICU admission (19%). Most of the adverse outcomes had good correlation with positive results of the exercise test. In conclusion, it appears that maternal exercise causes changes in FHR, which may be used to assess placental and fetal reserves.

Digital cardiotocography: What is the optimal sampling frequency?

Cardiotocography (CTG) is the most popular prenatal diagnostic test for establishing fetal health and consists in simultaneous recording of fetal heart rate (FHR, bpm) and maternal uterine contraction (UC, mmHg) traces. Typically, FHR and UC traces are visually analyzed and interpreted by clinicians. Recently, software applications like CTG Analyzer have been developed to support visual CTG interpretation by making it more objective and independent from clinician’s experience. Automatic CTG analysis requires CTG-traces digitalization and thus assessment of a correct sampling frequency (SF). Thus, this paper aims to investigate dependency of automatic CTG analysis on SF in order to identify optimal SF (OSF) for FHR and UC traces that minimizes computational efforts without jeopardizing CTG interpretation. To this aim, the “CTU-CHB intra-partum CTG database” was considered and visually annotated by an expert gynecologist. FHR and UC traces, originally sampled at 4 Hz, were down sampled at 2 Hz, 1 Hz, 0.4 Hz and 0.2 Hz, and automatically analyzed using CTG Analyzer. Eventually, results obtained through automatic analysis were compared to visual annotations, which were taken as reference. A cumulative statistical index (CSI), ranging from 0.00% to 100.00%, was defined as a linear combination of positive-predictive value, sensitivity, false-positive rate and false-negative rate. OSF was defined as the one that maximizes CSI. If CSI was showing the same value for more than one SF, the lowest SF was selected as the optimal since minimizing computational efforts. Results indicate that OSF for FHR is 2 Hz (CSI ≥ 85.41%), whereas OSF for UC is 0.2 Hz (CSI = 75.21%).

Antepartum and Intrapartum Fetal Assessment and Management

Antenatal surveillance and intrapartum fetal monitoring are routine components of obstetric care, particularly in the high-risk patient. The goal of antenatal testing is to reduce stillbirths in pregnancies with heightened risk. The goal of intrapartum monitoring is to reduce fetal acidemia, which can lead to asphyxia and long-term neurologic sequelae. Both antepartum and intrapartum monitoring of the fetal heart rate and its variability are sensitive to acidemia. Standard nomenclature exists for describing the features of fetal heart rate tracing. Ultrasonography is a useful adjunct to fetal heart rate monitoring, particularly for antenatal testing. The decision to initiate antenatal testing or intrapartum monitoring depends on many factors, particularly gestational age and maternal status. All forms of surveillance have high false-positive rates and poor positive predictive value. If the results of abnormal testing will not affect clinical management, testing should not be performed. This review contains 9 figures, 7 tables, and 50 references. Keywords: acidemia, antenatal testing, assessment, biophysical profile, electronic fetal monitoring, labor and delivery, nonstress test, stillbirth

The relationship between intrapartum fetal heart rate tracings and early neonatal outcomes

The relationship between intrapartum fetal heart rate tracings and early neonatal outcomes

52: Evaluation of an external fetal ECG monitoring system: a randomized controlled trial

To compare interpretability of two intrapartum abdominal fetal heart rate (FHR) monitoring strategies. We hypothesized that an external fetal electrocardiogram (fECG) monitoring system, a new technology using cable-free abdominal pads, would produce more interpretable FHR data compared to standard of care (SOC) external Doppler FHR monitoring. Randomized trial conducted at 4 Utah hospitals. Patients were enrolled at labor admission and randomized in blocks based on body mass index (BMI) to SOC or fECG. Primary outcome was the percentage of interpretable minutes of FHR tracing. An interpretable minute was defined as >25% FHR data present and no more than 25% continuous missing FHR data or artifact present. FHR tracings were read in blinded fashion by two reviewers. We also considered the rate of successful device set up, defined as the ability to obtain any interpretable FHR tracing, as well as the number of interpretable 10 minute FHR segments, device adjustments, clinical outcomes, and patient/provider device satisfaction as determined by Likert scale survey. We calculated that 100 patients per arm (200 total) would be needed to detect a 5% difference in interpretability with 95% power. 218 women were randomized, 108 to fECG and 110 to SOC (Figure). Device set up failure occurred more often in the fECG group (7.4% vs 0% for SOC). There were no differences in the primary outcome or 10 minute FHR segment analyses, but fECG produced more interpretable FHR tracing in BMI≥30 (Table). Maternal demographics and clinical outcomes were similar between arms. More device changes occurred in the fECG group, however fECG use required fewer nursing adjustments compared to SOC. There was no difference in physician device satisfaction between groups, but fECG generated higher patient device satisfaction scores. Although the primary outcome did not differ between groups, patients preferred the fECG system. Significant differences were noted with BMI stratification, where fECG outperformed SOC in women with BMI≥30. To our knowledge, this is the first randomized clinical comparison of an external fECG device and SOC. Further investigation should focus on predictors of fECG device failure and determining settings in which fECG may be the preferred and more cost-effective FHR monitoring strategy.View Large Image Figure ViewerDownload Hi-res image Download (PPT)