Umbilical Artery Acidemia Research Articles

Intrapartum electronic fetal heart rate monitoring to predict acidemia at birth with the use of deep learning

Electronic fetal monitoring is used in most US hospital births but has significant limitations in achieving its intended goal of preventing intrapartum hypoxic-ischemic injury. Novel deep learning techniques can improve complex data processing and pattern recognition in medicine. This study aimed to apply deep learning approaches to develop and validate a model to predict fetal acidemia from electronic fetal monitoring data. The database was created using intrapartum electronic fetal monitoring data from 2006 to 2020 from a large, multisite academic health system. Data were divided into training and testing sets with equal distribution of acidemic cases. Several different deep learning architectures were explored. The primary outcome was umbilical artery acidemia, which was investigated at 4 clinically meaningful thresholds: 7.20, 7.15, 7.10, and 7.05, along with base excess. The receiver operating characteristic curves were generated with the area under the receiver operating characteristic assessed to determine the performance of the models. External validation was performed using a publicly available Czech database of electronic fetal monitoring data. A total of 124,777 electronic fetal monitoring files were available, of which 77,132 had <30% missingness in the last 60 minutes of the electronic fetal monitoring tracing. Of these, 21,041 were matched to a corresponding umbilical cord gas result, of which 10,182 were time-stamped within 30 minutes of the last electronic fetal monitoring reading and composed the final dataset. The prevalence rates of the outcomes in the data were 20.9% with a pH of <7.2, 9.1% with a pH of <7.15, 3.3% with a pH of <7.10, and 1.3% with a pH of <7.05. The best performing model achieved an area under the receiver operating characteristic of 0.85 at a pH threshold of <7.05. When predicting the joint outcome of both pH of <7.05 and base excess of less than-10 meq/L, an area under the receiver operating characteristic of 0.89 was achieved. When predicting both pH of <7.20 and base excess of less than-10 meq/L, an area under the receiver operating characteristic of 0.87 was achieved. At a pH of <7.15 and a positive predictive value of 30%, the model achieved a sensitivity of 90% and a specificity of 48%. The application of deep learning methods to intrapartum electronic fetal monitoring analysis achieves promising performance in predicting fetal acidemia. This technology could help improve the accuracy and consistency of electronic fetal monitoring interpretation.

Oxytocin: physiology, pharmacology, and clinical application for labor management

Oxytocin is a peptide hormone that plays a key role in regulating the female reproductive system, including during labor and lactation. It is produced primarily in the hypothalamus and secreted by the posterior pituitary gland. Oxytocin can also be administered as a medication to initiate or augment uterine contractions. To study the effectiveness and safety of oxytocin, previous studies have randomized patients to low- and high-dose oxytocin infusion protocols either alone or as part of an active management of labor strategy along with other interventions. These randomized trials demonstrated that active management of labor and high-dose oxytocin regimens can shorten the length of labor and reduce the incidence of clinical chorioamnionitis. The safety of high-dose oxytocin regimens is also supported by no associated differences in fetal heart rate abnormalities, postpartum hemorrhage, low Apgar scores, neonatal intensive care unit admissions, and umbilical artery acidemia. Most studies reported no differences in the cesarean delivery rates with active management of labor or high-dose oxytocin regimens, thereby further validating its safety. Oxytocin does not have a predictable dose response, thus the pharmacologic effects and the amplitude and frequency of uterine contractions are used as physiological parameters for oxytocin infusion titration to achieve adequate contractions at appropriate intervals. Used in error, oxytocin can cause patient harm, highlighting the importance of precise administration using infusion pumps, institutional safety checklists, and trained nursing staff to closely monitor uterine activity and fetal heart rate changes. In this review, we summarize the physiology, pharmacology, infusion regimens, and associated risks of oxytocin.

Association between Intrapartum Cardiotocography and Umbilical Cord Blood pH in Term Pregnancies: A Cross-sectional Study in a Tertiary Care Centre, Kolkata, India

Introduction: Labour, a physiological process for majority of foetuses, often acts as a challenge to foetal reserves causing foetal hypoxia. Foetal monitoring with intrapartum cardiotocography is an important tool to enable timely intervention to reduce adverse neonatal outcomes like postnatal cerebral palsy. Aim: To determine an association between cardiotocography tracing and umbilical artery cord blood pH in term pregnancies in labour where the influence of drugs and the presence of other comorbid medical/obstetric adverse outcomes have been ruled out. Materials and Methods: This cross-sectional, hospital-based, observational study involved singleton uncomplicated term pregnancies with a normal baseline cardiotocography and spontaneous labour onset and progression admitted to the labour ward of R.G. Kar Medical College and Hospital, Kolkata, West Bengal, India. Intrapartum continuous cardiotocography traces were recorded and those showing abnormal traces were documented and delivery expedited within two hours. Total of 90 such consecutive women were included in the study and umbilical arterial cord blood sample was taken for all these pregnancies immediate postpartum. Cardiotocography traces were then statistically compared with cord blood parameters and the findings were computed using Statistical Package for the Social Sciences (SPSS) software version 22.0. Results: Out of 90 participants the mean age was 24.21±3.43 years, most (43, 47.8%) of them were in between 21 to 25 years. Of the abnormal traces, 51 (56.7%) were NICE Category II (Suspicious) and 39 (43.3%) were NICE category III (pathological). Cord blood analysis revealed that 40% had a pH&lt;7, 44.4% had blood lactate levels above 6 mmol/L and another 47.7% had a base deficit ≥12 mmol/L. On crosstabulation and Chi-square analysis, these were all found to be statistically significant (p-value &lt;0.05). Abnormalities of Foetal Heart Rate (FHR) and baseline variability had higher Odds ratio of predicting umbilical artery acidemia with Odd’s ratio for baseline variability abnormality as high as 2.768. Conclusion: Although there has been a rising trend towards operative deliveries, the overall incidence of neonatal morbidity due to cerebral palsy is still on the rise. Cardiotocography can be a very important tool to identify neonatal acidosis in “at risk” foetuses and helps in timely intervention giving long term best outcomes.

Fetal Heart Rate Nadir During Bradycardia and Umbilical Artery Acidemia at Birth

(Abstracted from Acta Obstet Gynecol Scand 2021;100:964–970) Although rare, fetal bradycardia caused by cord prolapse, placental abruption, or uterine rupture is associated with sudden and prolonged deceleration of the fetal heart rate. When this occurs, there is an association between the bradycardia-to-delivery interval and umbilical artery pH at birth.

6 High-dose versus standard-dose oxytocin regimens to augment labor in nulliparas: a double-blind randomized clinical trial

To determine whether, compared to standard-dose oxytocin (SDO), high-dose oxytocin (HDO) for labor augmentation reduces the risk of cesarean in nulliparas. This double-blind, single center randomized trial (NCT02487797) included nulliparas with singleton gestations≥36 weeks in spontaneous labor who required oxytocin for augmentation. Those being induced or non-English speaking were excluded. Women were randomized 1:1 to SDO (initial and incremental rate of 2 mU/min) or HDO (initial and incremental rate of 6 mU/min) dosing. Oxytocin solutions were prepared by pharmacists using different concentrations but infused at the same initial and incremental volume rates (2 mL/h) so investigators, patients, and clinicians could remain masked to allocation. The primary outcome was cesarean delivery. Secondary maternal outcomes were labor duration, chorioamnionitis, endometritis, and postpartum hemorrhage. Secondary perinatal outcomes were perinatal death, Apgar score <3 at 5 minutes, umbilical artery acidemia, NICU admission, and a severe composite adverse outcome. Analysis was by intention to treat with p<0.05 considered significant. We planned to enroll 501 women per group to achieve 80% power to demonstrate a 6.6% absolute difference in cesarean, assuming a baseline incidence of 20% in the SDO group. 1003 women were randomized from 9/28/15 to 9/1/20. The incidence of cesarean was not significantly different between the groups. However, there was a significantly lower median labor duration, and a significant reduction in the incidence of chorioamnionitis in the HDO group compared with SDO (Table). There were no significant differences in other outcomes, specifically no increased risk of adverse neonatal outcomes (e.g., cesarean for non-reassuring fetal status, umbilical artery acidemia, severe perinatal composite) with HDO. The use of HDO for labor management did not result in a change in the incidence of cesarean. However, HDO was associated with a significant reduction in chorioamnionitis and duration of labor augmentation, without increases in neonatal complications.

Intrapartum zigzag pattern of fetal heart rate is an early sign of fetal hypoxia: A large obstetric retrospective cohort study

IntroductionThe aim of the present study was to identify possible associations of fetal heart rate (FHR) patterns during the last 2 hours of labor with fetal asphyxia expressed by umbilical artery acidemia at birth and with neonatal complications in a large obstetric cohort.Material and methodsCardiotocographic recordings from 4988 singleton term childbirths over 1 year were evaluated retrospectively and blinded to the pregnancy and neonatal outcomes in a university teaching hospital in Helsinki, Finland. Umbilical artery pH, base excess and pO2, low Apgar scores at 5 minutes, need for intubation and resuscitation, early neonatal hypoglycemia, and neonatal encephalopathy were used as outcome variables. According to the severity of the neonatal complications at birth, the cohort was divided into three groups: no complications (Group 1), moderate complications (Group 2) and severe complications (Group 3).ResultsOf the 4988 deliveries, the ZigZag pattern (FHR baseline amplitude changes of >25 bpm with a duration of 2‐30 minutes) occurred in 11.7%, late decelerations in 41.0%, bradycardia episodes in 52.9%, reduced variability in 36.7%, tachycardia episodes in 13.9% and uterine tachysystole in 4.6%. No case of saltatory pattern (baseline amplitude changes of >25 bpm with a duration of >30 minutes) was observed. The presence of the ZigZag pattern or late decelerations, or both, was associated with cord blood acidemia (odds ratio [OR] 3.3, 95% confidence interval [CI] 2.3‐4.7) and severe neonatal complications (Group 3) (OR 3.3, 95% CI 2.4‐4.9). In contrast, no significant associations existed between the other FHR patterns and severe neonatal complications. ZigZag pattern preceded late decelerations in 88.7% of the cases. A normal FHR preceded the ZigZag pattern in 90.4% of the cases, whereas after ZigZag episodes, a normal FHR pattern was observed in only 0.9%.ConclusionsZigZag pattern and late decelerations during the last 2 hours of labor are significantly associated with cord blood acidemia at birth and neonatal complications. The ZigZag pattern precedes late decelerations, and the fact that normal FHR pattern precedes the ZigZag pattern in the majority of the cases suggests that the ZigZag pattern is an early sign of fetal hypoxia, which emphasizes its clinical importance.

51: Prolonged second stage and umbilical arterial acidemia in nulliparous women with neuraxial analgesia at term

51: Prolonged second stage and umbilical arterial acidemia in nulliparous women with neuraxial analgesia at term

758: Marked variability-cause for concern?

Continuous electronic fetal monitoring (EFM) is widely used to assess intrapartum fetal well-being during labor. However, little guidance is available regarding the frequency and interpretation of marked variability. We investigated the incidence of marked variability before delivery and its association with neonatal morbidity. This is a secondary analysis of a prospective cohort of 8,580 singleton deliveries from 2010-2015 at 37 weeks or beyond. EFM patterns during the 120 minutes prior to delivery were interpreted in 10-minute epochs. The primary outcomes were 1) a composite neonatal morbidity (death, respiratory distress, mechanical ventilation, suspected sepsis, meconium aspiration syndrome, therapeutic hypothermia, hypoxic-ischemic encephalopathy, & seizure) and 2) a composite adverse acid-base status (umbilical artery acidemia pH<7.10, elevated lactate ≥4 mmol/L, elevated base excess < -12). Outcomes were compared between women with and without marked variability defined as fluctuations in EFM amplitude of greater than 25 beats per minute ever in last 120 minutes. Adjusted risk ratios were estimated using multivariable logistic regression. Of the 8,580 women, 390 (4.5%) had marked variability before delivery. 757 (8.8%) of neonates had composite neonatal morbidity and 2,212 (26%) had composite adverse acid-base status. After adjusting for maternal age & obesity, women who had marked variability did not have increased risk of the composite neonatal morbidity 11% vs 8.7% aRR, [95% CI] 1.22 [0.91 1.63], though there was an increase in the risk of respiratory distress 7.2% vs 3.7% 1.85 [1.25, 2.70]. In contrast, there was an increased risk of composite adverse acid-base status 41.5% vs 25% 1.66 [1.47, 1.88]. This finding was driven by an increased risk of elevated lactate 42% vs 25% 1.66 [1.47, 1.88]. Marked variability occurred rarely before delivery and was not associated with increased risk of composite neonatal morbidity. However, marked variability was significantly associated with an increased risk of respiratory distress and elevated cord blood lactate.

Longitudinal evaluation of computerized cardiotocographic parameters throughout pregnancy in normal fetuses: a prospective cohort study.

The longitudinal cardiotocographic (CTG) changes throughout pregnancy in normal fetuses have never been fully described. We aimed at characterizing the evolution of CTG parameters in healthy fetuses, from 24 to 41weeks of gestation. A prospective cohort study was conducted in singleton fetuses without structural abnormalities on second-trimester ultrasound. At least one CTG was performed in each of the following intervals: 24-26weeks(+6d) , 27-29weeks(+6d) , 30-32weeks(+6d) , 33-35weeks(+6d) , 36-38weeks(+6d) and ≥39weeks; tracings were analyzed by the OMNIVIEW-SISPORTO 3.6 system. Cases of preterm delivery, fetal death, birthweight under the 10th percentile, low five-minute Apgar, umbilical artery acidemia or neonatal intensive care unit admission were subsequently excluded. A total of 1049 eligible tracings were obtained from 145 fetuses. There was a significant increase over time in average long-term variability (LTV), average short-term variability (STV), number of accelerations and uterine contractions. Conversely, fetal heart rate (FHR) baseline and number of decelerations decreased. A high inter-fetal variability was observed, but there was considerable intra-fetal consistency. Fetuses showing a marked decrease in FHR baseline and those with a marked increase in average LTV had a significantly lower birthweight. Cesarean section rate was significantly higher in cases with a decrease in average STV throughout gestation. This prospective longitudinal study shows an evolution in computerized CTG parameters during pregnancy, indicating the need to adapt interpretation criteria based on gestational age. The high inter-fetal variability and considerable intra-fetal consistency suggests the possible value of using each fetus as its own reference in serial assessments.

Mechanism of reduction of newborn metabolic acidemia following application of a rule-based 5-category color-coded fetal heart rate management framework

sObjective: We have reported a 7-fold reduction in newborn umbilical arterial (UA) metabolic acidemia after adoption of a rule-based 5-category color-coded fetal heart rate (FHR) management framework. We sought evidence for the relationship being causal by detailed analysis of FHR characteristics and acid–base status before and after training.Methods: Rates of UA pH and base excess (BE) were determined over a 5-year period in a single Japanese hospital, serving mainly low-risk patients, with 3907 deliveries. We compared results in the 2 years before and after a 6-month training period in the FHR management system. We used a previously published classification schema, which was linked to management guidelines.Results: After the training period, there was an increase in the percentage of normal patterns (23%), and a decrease in variable decelerations (14%), late decelerations (8%) and prolonged decelerations (12%) in the last 60 min of labor compared to the pre-training period. There was also a significant reduction in mean UA pH and BE in the groups with decelerations after introduction of the FHR management framework.Conclusions: The adoption of this FHR management system was associated with a reduction of decelerations and metabolic acidemia, without a change in cesarean or vacuum delivery rates. These results suggest that the obstetrical providers were able to better select for intervention those patients destined to develop more severe acidemia, demonstrating a possible causal relationship between the management system and reduced decelerations and metabolic acidemia.

Naegele Forceps Delivery and Association between Morbidity and the Number of Forceps Traction Applications: A Retrospective Study.

Objective. To present the method of Naegele forceps delivery clinically practiced by the lead author, its success rate, and morbidity and to evaluate the relationship between morbidity and the number of forceps traction applications. Methods. Naegele forceps delivery was performed when the fetal head reached station +2 cm, the forceps were applied in the maternal pelvic application, and traction was slowly and gently performed. In the past two years, Naegele forceps delivery was attempted by the lead author in 87 cases, which were retrospectively reviewed. Results. The numbers of traction applications were one in 64.7% of cases, two in 24.7%, and three or more in 10.7%. The success rate was 100%. No severe morbidity was observed in mothers or neonates. Neonatal facial injury occurred most commonly in cases with fetal head malrotation, elevated numbers of traction applications, and maternal complications. Umbilical artery acidemia most commonly occurred in cases with nonreassuring fetal status. The significant crude odds ratio for three or more traction applications was 20 in cases with malrotation. Conclusion. Naegele forceps delivery has a high success rate, but multiple traction applications will sometimes be required, particularly in cases with malrotation. Malrotation and elevated numbers of traction applications may lead to neonatal head damage.

Acute and massive bleeding from placenta previa and infants' brain damage

BackgroundAmong the causes of third trimester bleeding, the impact of placenta previa on cerebral palsy is not well known. AimsTo clarify the effect of maternal bleeding from placenta previa on cerebral palsy, and in particular when and how it occurs. Study designA descriptive study. SubjectsSixty infants born to mothers with placenta previa in our regional population-based study of 160,000 deliveries from 1998 to 2012. Premature deliveries occurring at<26weeks of gestation and placenta accreta were excluded. Outcome measuresPrevalence of cystic periventricular leukomalacia (PVL) and cerebral palsy (CP). ResultsFive infants had PVL and 4 of these infants developed CP (1/40,000 deliveries). Acute and massive bleeding (>500g within 8h) occurred at around 30–31weeks of gestation, and was severe enough to deliver the fetus. None of the 5 infants with PVL underwent antenatal corticosteroid treatment, and 1 infant had mild neonatal hypocapnia with a PaCO2 <25mmHg. However, none of the 5 PVL infants showed umbilical arterial acidemia with pH<7.2, an abnormal fetal heart rate monitoring pattern, or neonatal hypotension. ConclusionsOur descriptive study showed that acute and massive bleeding from placenta previa at around 30weeks of gestation may be a risk factor for CP, and requires careful neonatal follow-up. The underlying process connecting massive placental bleeding and PVL requires further investigation.

178: Mechanism of reduction of umbilical arterial metabolic acidemia following application of a standardized rule-based FHR management schema

178: Mechanism of reduction of umbilical arterial metabolic acidemia following application of a standardized rule-based FHR management schema

960 Complications in the Near Term and Term Infants with Severe Umbilical Artery Acidemia

Background and aims: Umbilical artery acidbase status is a useful marker of the fetal condition just before birth. The objective of our study was to determine the newborn complications in near term and term infants associated with umbilical artery acidemia of pH ≤ 7.10. Study design: We retrospectively reviewed the maternal and neonatal records of infant's ≥ 35 weeks, born between March 2007 and February 2010, with umbilical artery blood pH ≤ 7.10. Umbilical artery acidemia was classified as metabolic, respiratory and mixed. Results: 179 babies had an umbilical artery pH of ≤ 7.10, of which 59 had an umbilical artery pH < 7.00 and 120 had pH between 7.00 - 7.10. Overall 129 (72%) babies showed evidence of fetal distress; 82(45%) underwent emergency caesarean section, 41(22%) underwent instrumental vaginal delivery. Table below describes the neonatal complications in the two groups. Table Conclusion: The risk of moderate or severe hypoxic ischemic encephalopathy and neonatal seizures is high if umbilical artery pH is < 7.00 along with presence of mixed or metabolic acidosis. Hence these babies should have cerebral function monitoring at least for the first 24 hours.

Prediction of neonatal acidemia by computer analysis of fetal heart rate and ST event signals

The objective of the study was to evaluate the accuracy of computer analysis of fetal heart rate (FHR) and ST event signals in prediction of neonatal acidemia. One hundred forty-eight FHR tracings were evaluated to identify red alerts provided by the system, based on automated analysis of FHR and ST event signals, and compared with the occurrence of umbilical artery acidemia (pH < or =7.05). The presence of red alerts obtained sensitivity of 1.00 (95% confidence interval [CI], 0.56-1.00), specificity of 0.94 (95% CI, 0.89-0.97), positive predictive value (PPV) of 0.47 (95% CI, 0.22-0.72), negative predictive value (NPV) of 1 (95% CI, 0.96-1.00), positive likelihood ratio (PLR) of 17.6 (95% CI, 9.0-34.5), and negative likelihood ratio (NLR) of 0. When limiting analysis to red alerts that did not include ST data, sensitivity was 0.57 (95% CI, 0.20-0.88), specificity was 0.97 (95% CI, 0.92-0.99), PPV was 0.50 (95% CI, 0.17-0.82), NPV was 0.98 (95% CI, 0.93-0.99), PLR was 20.14 (95% CI, 6.3-64.2), and NLR was 0.44 (95% CI, 0.19-1.04). Computer analysis of FHR and ST event signals provide higher accuracy in predicting neonatal academia.

Factors associated with umbilical artery acidemia in term infants with low Apgar scores at 5min

Factors associated with umbilical artery acidemia in term infants with low Apgar scores at 5min

Factors associated with umbilical artery acidemia in term infants with low Apgar scores at 5 min

Objective To evaluate predictors of umbilical artery acidemia in term neonates with low Apgar score. Study design From a cohort of term singleton deliveries over a 13-year period, we selected neonates with 5-min Apgar score <7. Acidemia was defined as umbilical artery pH < 7.00 or base excess (BE) ≤−12 mmol/L. Three pathogenic processes of neonatal acidemia were evaluated: (1) intrauterine vascular disease, defined as preeclampsia, clinical diagnosis of placental abruption, birth weight <10th centile, or histologic evidence of placental infarction or severe vascular pathology, (2) intrauterine infection, defined as clinical chorioamnionitis, histologic chorioamnionitis, or early neonatal sepsis, and (3) acute intrapartum events, which included cases of cord prolapse, amniotic fluid embolism, uterine rupture, sudden and sustained fetal bradycardia or absence of FHR variability with a previously normal pattern, shoulder dystocia or complicated breech extraction. The associations of such processes with umbilical artery evidence of acidemia were tested using χ 2, Fisher's exact test, Student's t-test, and logistic regression, with P < 0.05 or odds ratio (OR) with 95% confidence interval (CI) not inclusive of the unity considered significant. Results Among the 27,395 neonates in the cohort, an Apgar score at 5 min <7 was recorded in 94 (0.32%) and it was associated with umbilical artery acidemia in 33 cases. Logistic regression analysis showed that intrauterine vascular disease was independently associated with umbilical cord acidemia ( P = 0.035, OR = 3.2, 95% CI = 1.1–9.7) whereas intrauterine infection (OR = 1.1, 95% CI 0.4–3.4) and acute intrapartum events (OR = 2.1 95% CI 0.6–7.0) were not. Conclusions Umbilical artery evidence of acidemia is present in 38% of term babies with low Apgar score and it is predominantly associated with chronic antepartum vascular disease. Neither intrauterine infection nor acute intrapartum events are significantly associated with umbilical artery acidemia.

Spinal Anesthesia for Cesarean Delivery and Umbilical Artery Acidemia

Spinal Anesthesia for Cesarean Delivery and Umbilical Artery Acidemia

Spinal anesthesia for cesarean delivery and umbilical artery acidemia

Spinal anesthesia for cesarean delivery and umbilical artery acidemia

Umbilical artery blood acid-base analysis and fetal heart rate baseline in the second stage of labor.

To evaluate the correlation between umbilical arterial acidemia and second-stage baseline fetal heart rate (FHR) abnormalities in Japanese newborn infants. Subjects were 365 newborns, born at term. Specimens were obtained from the umbilical artery as soon as possible after delivery and blood gas determinations were performed within 5 minutes of delivery. FHR monitoring was performed in the second stage. Umbilical arterial acidemia occurred in 54.1% of the newborns with moderate to severe bradycardia, in 27.3% with mild bradycardia, and in 19.3% with tachycardia, compared with only 1.3% of those with a normal FHR (p < 0.001). The mean umbilical arterial base excess was significantly greater in newborns with metabolic acidemia (-13.9+/-2.9 mmol/l) than in those with either mixed (-11.5+/-2.8 mmol/l) (p < 0.02) or respiratory (-9.1+/-3.2 mmol/l) (p < 0.01) acidemia. The second-stage baseline FHR abnormalities were highly correlated with an increased risk of umbilical arterial acidemia at delivery.