Correlation between total deceleration area in CTG records and cord blood pH in pregnancies with IUGR.

PURPOSE: Fetal cardiotocography is the most common method to assess fetal well-being during labor. Nevertheless, its predictive ability for acidemia is limited, both in low-risk and high-risk pregnancies (Nelson et al. in N Engl J Med 334: 613-9, 1996; Rinciples P et al. in Health and Human Development Workshop Report on Electronic Fetal Monitoring : Update on Definitions. no. 2007, 510-515, 2008), especially in high-risk pregnancies, such as those complicated by growth restriction. In this study we aim examine the association between deceleration and acceleration areas and other measure of fetal heart rate in intrapartum fetal monitoring and neonatal arterial cord blood pH in pregnancies complicated by growth restriction. MATERIALS AND METHODS: A retrospective cohort study of 100 deliveries complicated by growth restriction, delivered during 2018, was conducted. Known major fetal anomalies, non-vertex presentation and elective cesarean deliveries were excluded. Total deceleration and acceleration areas were calculated as the sum of the areas within the deceleration and acceleration, respectively. RESULTS: In deliveries complicated by growth restriction, cord blood pH is significantly associated with total deceleration area (p = 0.05) and correlates with cumulative duration of the decelerations (Spearman's rank -0.363, p < 0.05), and total acceleration area (-0.358, p < 0.05). By comparing the cord blood pH in deliveries with a total deceleration area that was above and below the median total deceleration area, we demonstrated a significant difference between the categories. CONCLUSIONS: Cord blood pH significantly correlates with total deceleration area and other fetal monitoring characteristics in neonates with growth restriction. Future studies using real-time, machine-learning based techniques of fetal heart rate monitoring, may provide population specific threshold values that will support bedside clinical decision making and perhaps achieve better outcomes.

Umbilical cord blood gases: probability of arterial or venous source in acidemia.

OBJECTIVES: Umbilical cord blood gases (UBG) may be a critical element in the assessment of a depressed newborn infant but in some cases the arterial or venous UBG source is uncertain making clinical and/or medical-legal interpretation difficult. Objective: to estimate the probability of an arterial (ProbAS) or venous (ProbVS) UBG source depending on blood gas parameters in acidemic cases. METHODS: A total of 56,703 pairs of concomitant arterial and venous (CAV) UBG results assayed over an 8.8-year period were analyzed. Specimen pairs with preanalytical issues, duplicate source, or physiologically out-of-range or uninterpretable results were excluded. The 3,579 CAV-UBGs with an arterial and venous pH 6.70 to 7.25 were analyzed. Generalized additive model (gam)-based binomial logistic regressions were used to determine the ProbAS and ProbVS according to the blood gas parameters. RESULTS: The relative differences between arterial and venous medians were: pO2 ‒47%, pCO2 22%, pH -11%, and BD 4%. Below a median of 2.4 kPa, the lower the pO2, the higher the ProbAS. Above this value, the higher the pO2, the lower the ProbAS. An Excel worksheet is provided to calculate ProbAS and ProbVS from the regression model for different combinations of pH, pCO2, and pO2 values. Considering ProbAS and ProbVS above a cutoff 0.8, the model correctly identified the source in 56% of cases while 41% were indeterminant and 3% were erroneous. CONCLUSIONS: The probability of an arterial or venous source of an umbilical blood gas can be estimated based on the pH, pCO2, and pO2 in most acidemic specimens.

Cardiotocography combined with ST analysis versus cardiotocography combined with fetal blood sampling in deliveries with abnormal CTG: a randomized trial.

PURPOSE: The aim was to investigate if intrapartum monitoring with cardiotocography (CTG) in combination with ST analysis (STAN) results in an improved perinatal outcome. METHODS: We performed a two-center randomized trial. 1013 women with term fetuses in cephalic presentation entered the trial. If a CTG showed intermediate or pathological abnormalities, they were offered fetal blood sampling (FBS) and inclusion if the pH value was above 7.25. They were randomized to either CTG + FBS or CTG + STAN. The primary outcome was neonatal metabolic acidosis, defined as umbilical cord arterial blood pH below 7.05, and base excess equal to or below -10. The secondary outcomes included operative vaginal delivery for fetal distress. RESULTS: The rate of metabolic acidosis was 0.8% in the CTG + FBS group and 1.5% in women in the CTG + STAN (P = 0.338). More women in the CTG + STAN group delivered by operative vaginal delivery (25.6% vs 33.5%, P = 0.006). Significantly fewer women in the CTG + STAN group had three to five (28.8% vs 11.0%, P = < 0.001) and six to ten fetal blood samples taken (3.4% vs 0.4%, P = < 0.001). CONCLUSION: CTG + STAN did not reduce the incidence of neonatal metabolic acidosis compared to CTG + FBS. CTG + STAN was, however, associated with an increased risk of operative vaginal delivery and a reduced use of FBS. If STAN is used for fetal surveillance, we recommend that it is combined with other methods, such as FBS, for confirmation of the need for operative delivery. CLINICALTRIALS: gov ID: NCT01699646. Date of registration: October 4, 2012 (retrospectively registered). https://clinicaltrials.gov/ct2/show/NCT01699646?id=NCT01699646&draw=2&rank=1.

Types of intrapartum hypoxia in the newborn at term with metabolic acidemia: A retrospective study.

INTRODUCTION: In the most recent recommendations of the International Federation of Gynecology and Obstetrics (FIGO), a chapter was dedicated to the physiological approach and to the description of fetal mechanisms developed to respond to hypoxia. Our objective was to classify the type of hypoxia in the case of metabolic acidemia and to describe the order of appearance of fetal heart rate abnormalities in cases of gradually evolving hypoxia. MATERIAL AND METHODS: 132 neonates born between 2018 and 2020 with acidemia were included. We excluded preterm birth, fetuses with congenital anomaly and twin pregnancies. Intrapartum cardiotocography traces were assigned to one of these four types of labor hypoxia: acute, subacute, gradually evolving and chronic hypoxia. For gradually evolving hypoxia, fetal heart rate abnormalities were described according to the FIGO classification. RESULTS: 36 cardiotocography traces (27.3%) were classified as acute hypoxia, 14 (10.6%) as subacute hypoxia, and 3 (3.2%) as chronic hypoxia; gradually evolving hypoxia occurred in 62 cases (47%). In 77.4% of cases of gradually evolving hypoxia, deceleration was the first anomaly to appear, with loss of variability and bradycardia appearing later. Increased fetal heart rate was observed immediately after late deceleration in 46.8% of cases and was followed by a loss of variability or saltatory rhythm in 37.1% of cases. CONCLUSIONS: In cases of metabolic acidemia at term, the most frequent situation observed was gradually evolving hypoxia, with an initial occurrence of decelerations. The sequence of fetal heart rate modifications was variable.

Neonatal outcomes of two-step delivery in low-risk pregnancy: A prospective observational study.

AIM: Extraction of the fetal body is typically performed immediately after delivery of the head in Western obstetric care. Reports justifying immediate extraction are few. Two-step delivery entails waiting for the next uterine contraction after delivery of the head. The present study evaluates neonatal asphyxia and respiratory impairment in two-step delivery using the head-to-body delivery interval. METHODS: This prospective observational study performed at a single birth clinic used the data of 262 low-risk pregnant women with two-step delivery. We measured the time interval of head-to-body delivery and correlation analysis and simple linear regression analysis between the head-to-body delivery interval and umbilical artery pH. The women were divided into two groups according to the head-to-body delivery interval: ≤60 or >60 s. The prevalence of neonatal asphyxia and neonatal respiratory impairment was compared between the groups. RESULTS: The mean head-to-body delivery interval was 88.9 ± 71.3 s. The umbilical artery pH tended to decrease with increasing head-to-body delivery interval; however, there was almost no correlation and the decline of pH was only 0.010 for every additional minute. Low Apgar score incidence at 5 min did not differ significantly between the groups. No cases of shoulder dystocia were reported, and tachypnea at 4 h after birth occurred in 3% of the births. CONCLUSIONS: A longer head-to-body delivery interval is not associated with negative outcomes in two-step delivery. We believe that two-step delivery could have some superior outcomes compared with one-step delivery outcomes, particularly as to improving fetal circulation and preventing shoulder dystocia.

Working-hour phenomenon in obstetrics is an attainable target to improve neonatal outcomes.

BACKGROUND: Giving birth in a health care facility does not guarantee high-quality care or favorable outcomes. The working-hour phenomenon describes adverse outcomes of institutional births outside regular working hours. OBJECTIVES: The objectives of the study were to evaluate whether the time of birth is associated with adverse neonatal outcomes and to identify the riskiest time periods for obstetrical care. STUDY DESIGN: This nationwide retrospective cohort study analyzed data from 2008 to 2016 from all 82 obstetric departments in Austria. Births at ≥ 23+0 gestational weeks with ≥500 g birthweight were included. Independent variables were categorized by the time of day vs night as core time (morning, day) and off hours (evening, nighttime periods 1-4). The composite primary outcome was adverse neonatal outcome, defined as arterial umbilical cord blood pH <7.2, 5 minute Apgar score <7, and/or admission to the neonatal intensive care unit. Multivariate logistic regression was used to develop a model to predict these adverse neonatal outcomes. RESULTS: Of 462,947 births, 227,672 (49.2%) occurred during off hours and had a comparable distribution in all maternity units, regardless of volume (<500 births per year: 50.3% during core time vs 49.7% during off hours; ≥500 births per year: 50.7% core time vs 49.3% off hours; perinatal tertiary center: 51.2% core time vs 48.8% off hours). Furthermore, most women (35.8-35.9%) gave birth between 2:00 and 5:59 am (night periods 3 and 4). After adjustment for covariates, we found that adverse neonatal outcomes also occurred more frequently during these night periods 3 and 4, in addition to the early morning period (night 3: odds ratio, 1.05; 95% confidence interval, 1.03-1.08; P < .001; night 4: odds ratio, 1.08; 95% confidence interval, 1.05-1.10; P < .001; early morning period: odds ratio, 1.05; 95% confidence interval, 1.02-1.08; P < .001). The adjusted odds for adverse outcomes were lowest for births between 6:00 and 7:59 pm (odds ratio, 0.96; 95% confidence interval, 0.93-0.99; P = .006). CONCLUSION: There is an increased risk of adverse neonatal outcomes when giving birth between 2:00 and 7:59 am. The so-called working-hour phenomenon is an attainable target to improve neonatal outcomes. Health care providers should ensure an optimal organizational framework during this time period.

Computerized analysis of cardiotocograms and ST signals is associated with significant reductions in hypoxic-ischemic encephalopathy and cesarean delivery: an observational study in 38,466 deliveries.

BACKGROUND: Intrapartum cardiotocography is widely used in high-resource countries and remains at the center of fetal monitoring and the decision to intervene, but there is ample evidence of poor reliability in visual interpretation as well as limited accuracy in identifying fetal hypoxia. Combined monitoring of intrapartum cardiotocography and ST segment signals was developed to increase specificity, but analysis relies heavily on intrapartum cardiotocography interpretation and is therefore also affected by the previously referred problems. Computerized analysis was developed to overcome these limitations, aiding in the quantification of parameters that are difficult to evaluate visually, such as variability, integrating the complex guidelines of combined intrapartum cardiotocography and ST analysis, and using visual and sound alerts to prompt health care professionals to reevaluate features associated with fetal hypoxia. OBJECTIVE: The objective of the study was to evaluate the effect of introducing a central fetal monitoring system with computerized analysis of intrapartum cardiotocography and ST signals into the labor ward of a tertiary care university hospital in which all women are continuously monitored with intrapartum cardiotocography. The incidence of adverse perinatal outcomes and intervention rates was evaluated over time. STUDY DESIGN: In this retrospective cohort study, yearly rates of hypoxic-ischemic encephalopathy, instrumental vaginal delivery, overall cesarean delivery, and urgent cesarean delivery were obtained from the hospital's clinical databases. The rates occurring in the period from January 2001 to December 2003, before the introduction of the central monitoring system with computerized analysis of intrapartum cardiotocography and ST signals (Omniview-SisPorto), were compared with those occurring from January 2004 to December 2014, after the introduction of the system. All rates were calculated with 95% confidence intervals. RESULTS: A total of 38,466 deliveries occurred during this period. After introduction of the system, there was a significant decrease in the number of hypoxic-ischemic encephalopathy cases per 1000 births (5.3%, 95% confidence interval [4.0-7.0] vs 2.2%, 95% confidence interval [1.7-2.8]; relative risk, 0.42, 95% confidence interval [0.29-0.61]), overall cesarean delivery rates (29.9%, 95% confidence interval [28.9-30.8] vs 28.3%, 95% confidence interval [27.8-28.8]; relative risk, 0.96, 95% confidence interval [0.92-0.99]), and urgent cesarean deliveries (21.6%, 95% confidence interval [20.7-22.4] vs 19.2%, 95% confidence interval [18.8-19.7]; relative risk, 0.91, 95% confidence interval [0.87-0.95]). The instrumental vaginal delivery rate increased (19.5%, 95% confidence interval [18.7-20.3] vs 21.4%, 95% confidence interval [21.0-21.9; relative risk, 1.07, 95% confidence interval 1.02-1.13]. CONCLUSION: Introduction of computerized analysis of intrapartum cardiotocography and ST signals in a tertiary care hospital was associated with a significant reduction in the incidence of hypoxic-ischemic encephalopathy and a modest reduction in cesarean deliveries.

Peripartum events associated with severe neurologic morbidity and mortality among acidemic neonates.

PURPOSE: To identify peripartum events that may predict the development of short-term neurologic morbidity and mortality among acidemic neonates. METHODS: Retrospective case-control study conducted at a single-teaching hospital on data from January 2010 to December 2015. The study cohort group included all acidemic neonates (cord artery pH ≤ 7.1) born at ≥ 34 weeks. Primary outcome was a composite including any of the following: neonatal encephalopathy, convulsions, intra-ventricular hemorrhage, or neonatal death. The study cohort was divided to the cases group, i.e., acidemic neonates who had any component of the primary outcome, and a control group, i.e., acidemic neonates who did not experience any component of the primary outcome. RESULTS: Of all 24,311 neonates born ≥ 34 weeks during the study period, 568 (2.3%) had a cord artery pH ≤ 7.1 and composed the cohort study group. Twenty-one (3.7%) neonates composed the cases group. Multivariate logistic regression analysis revealed that cases were significantly more likely to have experienced placental abruption (OR 18.78; 95% CI 5.57-63.26), born ≤ 2500 g (OR 13.58; 95% CI 3.70-49.90), have meconium (OR 3.80; 95% CI 1.20-11.98) and cord entanglement (OR 5.99; 95% CI 1.79-20.06). The probability for developing the composite outcome rose from 3.7% with isolated acidemia to 97% among neonates who had all these peripartum events combined with intrapartum fetal heart rate tracing category 2 or 3. CONCLUSION: Neonatal acidemia carries a favorable outcome in the vast majority of cases. In association with particular antenatal and intrapartum events, the short-term outcome may be unfavorable.

Computer Vision for Identification of Increased Fetal Heart Variability in Cardiotocogram.

INTRODUCTION: Increased fetal heart rate variability (IFHRV), defined as fetal heart rate (FHR) baseline amplitude changes of >25 beats per minute with a duration of ≥1 min, is an early sign of intrapartum fetal hypoxia. This study evaluated the level of agreement of machine learning (ML) algorithms-based recognition of IFHRV patterns with expert analysis. METHODS: Cardiotocographic recordings and cardiotocograms from 4,988 singleton term childbirths were evaluated independently by two expert obstetricians blinded to the outcomes. Continuous FHR monitoring with computer vision analysis was compared with visual analysis by the expert obstetricians. FHR signals were graphically processed and measured by the computer vision model labeled SALKA. RESULTS: In visual analysis, IFHRV pattern occurred in 582 cardiotocograms (11.7%). Compared with visual analysis, SALKA recognized IFHRV patterns with an average Cohen's kappa coefficient of 0.981 (95% CI: 0.972-0.993). The sensitivity of SALKA was 0.981, the positive predictive rate was 0.822 (95% CI: 0.774-0.903), and the false-negative rate was 0.01 (95% CI: 0.00-0.02). The agreement between visual analysis and SALKA in identification of IFHRV was almost perfect (0.993) in cases (N = 146) with neonatal acidemia (i.e., umbilical artery pH <7.10). CONCLUSIONS: Computer vision analysis by SALKA is a novel ML technique that, with high sensitivity and specificity, identifies IFHRV features in intrapartum cardiotocograms. SALKA recognizes potential early signs of fetal distress close to those of expert obstetricians, particularly in cases of neonatal acidemia.

Prophylactic phenylephrine infusion versus treatment with vasopressor bolus as needed during non-urgent cesarean delivery and neonatal acidemia: a retrospective cohort study (2016-2021).

INTRODUCTION: Prophylactic vasopressor administration reduces spinal hypotension during cesarean delivery, however the effects of vasopressor administration on neonatal acidemia remain uncertain. We examined the occurrence of neonatal acidemia in the setting of non-urgent cesarean delivery and compared outcomes between cases receiving prophylactic phenylephrine infusion versus cases treated with boluses of phenylephrine. METHODS: Retrospective cohort study with ethical approval, comparing non-urgent cesarean delivery cases performed under spinal anesthesia (2016 to 2021), receiving either prophylactic phenylephrine infusion or boluses as needed. Data were collected from anesthesia and labor ward electronic medical records. Records with missing pH or missing blood pressure data were excluded. The independent variable was prophylactic phenylephrine administration, a strategy implemented following international recommendations in 2018. The main outcome was neonatal acidemia, defined as umbilical artery pH < 7.1. The secondary outcome was maternal hypotension, defined as at least one systolic blood pressure (SBP) measurement below 100 mmHg or below 80% baseline. RESULTS: A total of 4392 patients were included in the final analysis; 1318 (30.0%) received prophylactic phenylephrine infusion. Neonatal acidemia (umbilical artery pH < 7.1) occurred in 28 (2.1%) cases receiving prophylactic phenylephrine versus 50 (1.6%) treated with boluses as needed (p = 0.188). Prophylactic phenylephrine infusion was not associated with occurrence of neonatal acidemia (aOR 0.83; 95% CI 0.52 to 1.33, p = 0.435). Prophylactic phenylephrine infusion was associated with a reduced spinal hypotension rate when defined as SBP < 100 mmHg (OR 0.47; 95% CI 0.37 to 0.57; p < 0.001), with similar results when hypotension was defined as a drop below 80% or 90% of baseline SBP. CONCLUSION: In this pragmatic study, prophylactic phenylephrine infusion was associated with a reduction in maternal spinal hypotension, but not reduced neonatal acidemia.

The Correlation Between the Total Decelerations and Accelerations Areas and Cord Blood pH in Women with Low-Risk Pregnancies.

Fetal acidosis among low-risk pregnancies is not common; however, identifying those at risk for this complication antenatally is of great interest. We aimed to assess the correlation between the total decelerations area during the last 120 min of fetal monitoring prior to delivery and neonatal acidemia in low-risk pregnancies and whether the total acceleration area has a protective effect in the presence of decelerations. A retrospective cohort study was conducted among women with term low-risk pregnancies. A researcher blinded to fetal outcomes interpreted electronic fetal monitor patterns during the 120 min prior to delivery. The primary outcome was fetal acidemia, defined as umbilical artery pH below 7.10. The correlation between the total decelerations and accelerations areas and cord blood pH was tested using the Spearman correlation coefficient. A total of 109 women were included and of these, six (5.5%) delivered infants with cord blood pH < 7.10. A significant correlation was demonstrated between the total decelerations area and cord blood pH (p = 0.01). No correlation was found between the total accelerations area and cord blood pH. Among low-risk pregnancies, a correlation was found between the total decelerations area but not the total accelerations area during the final 120 min of labor and cord blood pH.

Intrapartum electronic fetal monitoring features associated with a clinical diagnosis of nonreassuring fetal status.

BACKGROUND: Nonreassuring fetal status detected by continuous electronic fetal monitoring accounts for almost 1 in 4 primary cesarean deliveries. However, given the subjective nature of the diagnosis, there is a need to identify the electronic fetal monitoring patterns that are clinically considered nonreassuring. OBJECTIVE: This study aimed to describe which electronic fetal monitoring features are most commonly associated with first-stage cesarean delivery for nonreassuring fetal status, and to evaluate the risk of neonatal acidemia following cesarean delivery for nonreassuring fetal status. STUDY DESIGN: This was a nested case-control study in a prospectively collected cohort of patients with singleton pregnancies at ≥37 weeks' gestation, admitted in spontaneous labor or for induction of labor from 2010 to 2014 at a single tertiary care center. Patients with preterm pregnancies, multiple gestations, planned cesarean delivery, or nonreassuring fetal status in the second stage of labor were excluded. Cases were identified as having nonreassuring fetal status on the basis of what was documented in the operative note by the delivering physician. Controls were patients without nonreassuring fetal status within 1 hour of delivery. Cases were matched to controls in a 1:2 ratio by parity, obesity, and history of cesarean delivery. Electronic fetal monitoring data were abstracted by credentialed obstetrical research nurses for the 60 minutes before delivery. The primary exposure of interest was the incidence of high-risk category II electronic fetal monitoring features in the 60 minutes before delivery; in particular, the incidence of minimal variability, recurrent late decelerations, recurrent variable decelerations, tachycardia, and >1 prolonged deceleration were compared between groups. We also compared neonatal outcomes between cases and controls, including fetal acidemia (umbilical artery pH <7.1), other umbilical artery gas analytes, and neonatal and maternal outcomes. RESULTS: Of the 8580 patients in the parent study, 714 (8.3%) underwent cesarean delivery for nonreassuring fetal status in the first stage of labor. Patients diagnosed with nonreassuring fetal status requiring cesarean delivery were more likely to have recurrent late decelerations, >1 prolonged deceleration, and recurrent variable decelerations compared with controls. More than 1 prolonged deceleration was associated with 6 times increased rate of nonreassuring fetal status diagnosis resulting in cesarean delivery (adjusted odds ratio, 6.73 [95% confidence interval, 2.47-8.33]). Rates of fetal tachycardia were similar between groups. Minimal variability was less common in the nonreassuring fetal status group compared with controls (adjusted odds ratio, 0.36 [95% confidence interval, 0.25-0.54]). Compared with control deliveries, cesarean delivery for nonreassuring fetal status was associated with nearly 7 times higher risk of neonatal acidemia (7.2% vs 1.1%; adjusted odds ratio, 6.93 [95% confidence interval, 3.83-12.54]). Composite neonatal morbidity and composite maternal morbidity were more likely among patients delivered for nonreassuring fetal status in the first stage (3.9% vs 1.1%; adjusted odds ratio, 5.70 [2.60-12.49]; and 13.3% vs 8.0%; adjusted odds ratio, 1.99 [1.41-2.80]). CONCLUSION: Although multiple category II electronic fetal monitoring features have been traditionally linked to acidemia, the presence of recurrent late decelerations, recurrent variable decelerations, and prolonged decelerations seemed to concern obstetricians enough to surgically intervene for nonreassuring fetal status. A clinical intrapartum diagnosis of nonreassuring fetal status in the setting of these electronic fetal monitoring features is also associated with increased risk of acidemia, suggesting clinical validity to the diagnosis of nonreassuring fetal status.

The Impact of Total Deceleration Area and Fetal Growth on Neonatal Acidemia in Vacuum Extraction Deliveries.

We aimed to investigate the correlation between total deceleration area (TDA), neonatal birthweight and neonatal acidemia in vacuum extractions (VEs). This is a retrospective study in a tertiary hospital, including VE performed due to non-reassuring fetal heart rate (NRFHR). Electronic fetal monitoring during the 120 min preceding delivery was interpreted by two obstetricians who were blinded to neonatal outcomes. TDA was calculated as the sum of the area under the curve for each deceleration. Neonatal birthweights were classified as low (<2500 g), normal (2500-3999 g) or macrosomic (>4000 g). A total of 85 VEs were analyzed. Multivariable linear regression, adjusted for gestational age, nulliparity and diabetes mellitus, revealed a negative correlation between TDA in the 60 min preceding delivery and umbilical cord pH. For every 10 K increase in TDA, the cord pH decreased by 0.02 (p = 0.038; 95%CI, -0.05-0.00). The use of the Ventouse-Mityvac cup was associated with a 0.08 decrease in cord pH as compared to the Kiwi OmniCup (95%CI, -0.16-0.00; p = 0.049). Low birthweights, compared to normal birthweights, were not associated with a change in cord pH. To conclude, a significant correlation was found between TDA during the 60 min preceding delivery and cord pH in VE performed due to NRFHR.

Shoulder Dystocia: Challenging Basic Assumptions.

Most of our knowledge pertaining to this obstetric emergency has emanated from case reports and retrospective studies that have subsequently resulted in empirical management protocols. This article has identified the existence of large gaps in our clinical knowledge base regarding the prevention and resolution of shoulder dystocia, as well as its long-term sequelae. We have attempted to challenge current recommendations regarding whether prophylactic cesarean delivery should be performed based on estimated fetal weight alone or a prior history of shoulder dystocia, shoulder dystocia management techniques, what defines "excessive" traction, and the role of simulation training for all clinicians.

Correlation between total deceleration area and fetal cord blood pH in neonates complicated with meconium-stained amniotic fluid at term.

OBJECTIVE: To assess the correlation between total area under the Curve (AUC) of decelerations and accelerations and neonatal acidemia in pregnancies complicated with meconium-stained amniotic fluid (MSAF). METHODS: A retrospective cohort study was conducted among women who delivered with a diagnosis of MSAF. Electronic fetal monitoring (EFM) patterns 120 min before delivery were interpreted by a researcher blinded to fetal outcomes. The primary outcome was fetal acidemia, defined as umbilical artery pH below 7.10. The correlation was tested using the Spearman correlation coefficient. RESULTS: A total of 102 women were included; 24 delivered infants with cord blood pH < 7.20, and only five delivered infants with cord blood pH < 7.10. A significant correlation was demonstrated between total AUC of decelerations and accelerations and cord blood pH (P = 0.02). A sub-analysis according to gestational age at delivery (up to and beyond 40 weeks) was conducted. A significant correlation was demonstrated (P = 0.02) only in the term group(n = 37). CONCLUSION: A correlation was demonstrated between total AUC of decelerations and accelerations and cord blood pH in neonates with MSAF. This correlation was significant for neonates delivered before 40 weeks of gestation, but not for those delivered after 40 weeks of gestation.

Total intrapartum fetal reperfusion time (fetal resilience) and neonatal acidemia.

OBJECTIVE: The main objective is to study the predictive capacity of intrapartum total fetal reperfusion (fetal resilience) by itself or in combination with other parameters as a predictor of neonatal acidemia. STUDY DESIGN: A retrospective case-control study was carried out at the Miguel Servet University Hospital (Zaragoza, Spain) on a cohort of 5694 pregnant women between June 2017 and October 2018. Maternal, perinatal, and cardiotocographic records were collected. Two reviewers blindly described the monitors with the American College of Obstetricians and Gynecologists (ACOG) categorizations and parameters and the non-ACOG parameters. Neonatal acidemia was defined as pH <7.10. The parameters analyzed to predict acidemia were evaluated using the sensitivity for specificity 90% value, and the area under the receiver operating characteristic curve. RESULTS: We recorded 192 infants with acidemia, corresponding to a global acidemia rate of 3.4%. Of these, 72 were excluded for lack of criteria, leaving 120 patients with arterial acidemia included in the study and 258 in the control group. The sensitivity (specificity 90%) of detection of acidemia was 42% for the ACOG III categorization (AUC, 0.524: 95% CI, 0.470-0.578), 24% for fetal reperfusion (AUC, 0.704: 95% CI, 0.649-0.759), 27% for total area of decelerations (AUC, 0.717: 95% CI, 0.664-0.771) and 50% for the multivariate model built from total reperfusion time (AUC, 0.826: 95% CI, 0.783-0.869). The total reperfusion time corresponding to a false negative rate of 10% is 23.75 min, with 28% of fetuses above this time. The AUC and sensitivity for a false negative rate of 10% are equivalent for deceleration area and time of reperfusion (p = .504). CONCLUSION: The total reperfusion time (fetal resilience) and total deceleration area are non-ACOG parameters with a good predictive ability for neonatal acidemia, higher than the ACOG III classification and without statistical differences between them. The discrimination ability of total reperfusion time can be improved using a multivariate model. As a cutoff for its use we suggest 23.75 min in 30 min corresponding to an acidemic classification rate of 90%. New parameters in combination with other maternal, obstetrics, or fetal variables, are required for the interpretation of fetal well-being.

The risk of meconium aspiration syndrome (MAS) increases with gestational age at term.

OBJECTIVE: To examine the risk of meconium aspiration syndrome (MAS) by the week of gestational age in pregnancies with meconium-stained amniotic fluid (MSAF). METHODS: This is a retrospective cohort study derived from term pregnancies at a single tertiary institution over an 18-year period. Outcomes analyzed included MAS, acidemia, and Apgar scores. Univariate analysis was performed using chi-square and multivariable logistic regression was used to adjust for potential confounders. RESULTS: A total of 34,303 deliveries ≥37 weeks were included; 23.7% were complicated by MSAF. Of the total study cohort, 272 (0.7%) neonates were diagnosed with MAS; this represented 3% of all deliveries complicated by MSAF. In the presence of MSAF, the risk of MAS increased with gestational age, from 1.3% at 38 weeks to 4.8% at 42 weeks (p < .001). Similarly, the risk of acidemia increased from 3.0% at 38 weeks to 7.0% at 42 weeks (p < .001). These findings were also demonstrated in patients with MAS in the absence of MSAF. The risk for both MAS and acidemia in the presence of MSAF persisted after controlling for potential confounders (aOR 1.31 [95% CI 1.18-1.46] and 1.20 [95% CI 1.05-1.37], respectively). CONCLUSION: In women with MSAF, as gestational age increases, the risk of meconium aspiration syndrome also increases. Other factors with late-term and post-term pregnancy besides the presence of meconium may contribute to the evolution of MAS.

Neonatal cord blood eucapnic pH: A potential biomarker predicting the need for transfer to the NICU.

INTRODUCTION: The best biomarker for neonatal metabolic acidosis (NMA) and its related complications is still a matter of debate. Umbilical artery (Ua) cord pH is not sufficiently specific, as is lactatemia, while base deficit is considered to offer no added value. From a physiological point of view, the calculated neonatal eucapnic pH is a more specific marker for neonatal metabolic acidosis and may be a better predictor of birth complications of hypoxic origin, because complications related to asphyxia are always preceded by neonatal depression leading to a transfer to a neonatal intensive care unit (NICU) for close monitoring. OBJECTIVE: This study aimed to test the hypothesis that in a group of neonates with significant acidemia, neonatal eucapnic pH (pH euc-n) predicts NICU admission better than the Ua cord pH does. METHODS: From a cohort of 5,392 infants all born at ≥35 weeks' gestation, we identified a group of 30 cases with Ua cord pH <7.0. We calculated the area under the curve (AUC) for pH euc-n and Ua cord pH using the receiver-operating characteristic (ROC) curve and compared the performance of these biological markers in predicting transfer to the NICU. Cut-off points were determined by selecting the best value of the positive likelihood ratio that maximizes the accuracy of prediction. RESULTS: From the 30 newborns diagnosed with significant acidemia, four infants were transferred to the NICU. No case of neonatal encephalopathy was observed. In these infants, the pH euc-n AUC (0.66) was significantly higher than the Ua cord pH AUC (0.44) (P<0.005), with the best pH euc-n cut-off value at 7.11. CONCLUSION: Despite the study limitations, our results suggest that pH euc-n is a better marker than Ua pH for predicting admission to the NICU in newborns with acidemia at birth. These are preliminary results and further investigations are mandatory in larger population samples to confirm these findings and to determine the optimal cut-off value for pH euc-n for the most accurate prediction of a complicated transition to extrauterine life and, potentially, neonatal hypoxic-ischemic encephalopathy.

Effects of Vasoactive Medications and Maternal Positioning During Cesarean Delivery on Maternal Hemodynamics and Neonatal Acid-Base Status.

Maternal hemodynamics, positioning, and anesthesia technique for cesarean delivery influence neonatal acid-base balance; direct effects from drugs that cross the placenta also have an influence. Spinal anesthesia limits fetal exposure to depressant drugs and avoids maternal airway instrumentation, but is associated with hypotension. Hypotension may be prevented/treated with vasopressors and intravenous fluids. Current evidence supports phenylephrine as the first-line vasopressor. Fifteen degrees of lateral tilt during cesarean delivery has been advocated to relieve vena caval obstruction, but routine use may be unnecessary in healthy nonobese women having elective cesarean delivery if maternal blood pressure is maintained near baseline.

Intrapartum Fetal Heart Rate: A Possible Predictor of Neonatal Acidemia and APGAR Score.

Background: Predicting perinatal outcomes based on patterns of fetal heart rate (FHR) remains a challenge. The aim of this study was to evaluate intrapartum FHR variability as predictor for neonatal acidemia and APGAR score. Methods: This was a retrospective observational study of 552 childbirths. Multivariable linear regression models were used to assess the association between FHR variability and each of the following outcomes: arterial cord blood pH and base deficit, Apgar 1, and 5 scores. Variables used for adjustment were maternal age, comorbidities (gestational diabetes, preeclampsia, maternal fever, and hypertension), parity, gravidity, uterine contractions, and newborn gestational age, and weight at birth. Results: The following factors were associated with an increased risk of metabolic acidosis and low Apgar scores at birth: increased mean and coefficient of variation (CV) of the FHR, type of delivery and decreased parity. Each 10-beat/min increase in the FHR was associated with an increase of 0.43 mEq/L in the base deficit, and a decrease of 0.01 in the pH, 0.2 in the Apgar 1, and 0.14 in the Apgar 5 scores. Each 10% increase in the CV of the FHR was associated with an increase of 4.05 mEq/L in the base deficit and a decrease of 0.13 in the pH, 1.31 in the Apgar 1, and 0.86 in the Apgar 5 scores. Conclusion: These data suggest the intrapartum FHR variability is physiologically relevant and can be used for predicting the acidemia and Apgar scores at birth of the newborn infants without severe cases of morbidity and from uncomplicated pregnancies.