The peripheral chemoreflex: indefatigable guardian of fetal physiological adaptation to labour

Neonatal Encephalopathy is a Complex Phenotype Representing Reproductive and Pregnancy Exposome Effects on the Maternal-Placental-Fetal Triad

Reproductive, pregnancy, and placental exposomes influence the fetal neural exposome through toxic stressor interplay, impairing the maternal-placental-fetal (MPF) triad. Neonatal encephalopathy represents different clinical presentations based on complex time-dependent etiopathogenetic mechanisms including hypoxia-ischemia that challenge diagnosis and prognosis. Reproductive, pregnancy, and placental exposomes impair the fetal neural exposome through toxic stressor interplay within the MPF triad. Long intervals often separate disease onset from phenotype. Interdisciplinary fetal-neonatal neurology training, practice, and research closes this knowledge gap. Maintaining reproductive health preserves MPF triad health with life-course benefits.

The utility of fetal heart rate deceleration's descending slope in searching for a non-National Institute of Child Health and Human Development parameter for the detection of fetal acidosis

OBJECTIVE

To identify new parameters predicting fetal acidemia.

METHODS

A retrospective case-control study in a cohort of deliveries from a tertiary referral hospital-based cohort deliveries in Zaragoza, Spain between 2018 and 2021 was performed. To predict fetal acidemia, the NICHD categorizations and non-NICHD parameters were analyzed in the electronic fetal monitoring (EFM). Those included total reperfusion time, total deceleration area and the slope of the descending limb of the fetal heart rate of the last deceleration curve. The accuracy of the parameters was evaluated using the specificity for (80%, 85%, 90%, 95%) sensitivity and the area under the receiver operating characteristic curve (AUC).

RESULTS

A total of 10 362 deliveries were reviewed, with 224 cases and 278 controls included in the study. The NICHD categorizations showed reasonable discriminatory ability (AUC = 0.727). The non-NICHD parameters measured during the 30-min fetal monitoring, total deceleration area (AUC = 0.807, 95% CI: 0.770, 0.845) and total reperfusion time (AUC = 0.750, 95% CI: 0.707, 0.792), exhibited higher discriminatory ability. The slope of the descending limb of the fetal heart rate of the last deceleration curve had the best AUC value (0.853, 95% CI: 0.816, 0.889). The combination of total deceleration area or total reperfusion time with the slope demonstrated high discriminatory ability (AUC = 0.908, 95% CI: 0.882, 0.933; specificities of 71.6% and 72.7% for a sensitivity of 90%).

CONCLUSIONS

The slope of the descending limb of the fetal heart rate of the last deceleration curve is the strongest predictor of fetal acidosis, but its combination with the total reperfusion time shows better clinical utility.

Interdisciplinary fetal-neonatal neurology training improves brain health across the lifespan

Integrated fetal, neonatal, and pediatric training constitute an interdisciplinary fetal-neonatal neurology (FNN) program. A dynamic neural exposome concept strengthens curriculum content. Trainees participate in mentoring committee selection for guidance during a proposed two-year program. Prenatal to postnatal clinical learning re-enforces early toxic stressor interplay that influences gene-environment interactions. Maternal-placental-fetal triad, neonatal, or childhood diseases require diagnostic and therapeutic decisions during the first 1,000 days when 80 % of neural connections contribute to life-course phenotypic expression. Pediatric follow-up through 3 years adjusts to gestational ages of preterm survivors. Cumulative reproductive, pregnancy, pediatric and adult exposome effects require educational experiences that emphasize a principle-to-practice approach to a brain capital strategy across the lifespan. More rigorous training during fetal, neonatal, and pediatric rotations will be offered to full time trainees. Adult neurology residents, medical students, and trainees from diverse disciplines will learn essential topics during time-limited rotations. Curriculum content will require periodic re-assessments using educational science standards that maintain competence while promoting creative and collaborative problem-solving. Continued career-long learning by FNN graduates will strengthen shared healthcare decisions by all stakeholders. Recognition of adaptive or maladaptive neuroplasticity mechanisms requires analytic skills that identify phenotypes associated with disease pathways. Developmental origins and life-course concepts emphasize brain health across the developmental-aging continuum, applicable to interdisciplinary research collaborations. Social determinants of health recognize diversity, equity, and inclusion priorities with each neurological intervention, particularly for those challenged with disparities. Diagnostic and therapeutic strategies must address resource challenges particularly throughout the Global South to effectively lower the worldwide burden of neurologic disease. Sustainable development goals proposed by the World Health Organization offer universally applicable guidelines in response to ongoing global and regional polycrises. Gender, race, ethnicity, and socio-economic equality promote effective preventive, rescue and reparative neuroprotective interventions. Global synergistic efforts can be enhanced by establishing leadership within academic teaching hubs in FNN training to assist with structure and guidance for smaller healthcare facilities in each community that will improve practice, education and research objectives. Reduced mortality with an improved quality of life must prioritize maternal-pediatric health and well-being to sustain brain health across each lifespan with transgenerational benefits.

Clinical decisions in fetal-neonatal neurology II: Gene-environment expression over the first 1000 days presenting as "four great neurological syndromes"

Interdisciplinary fetal-neonatal neurology (FNN) training considers a woman's reproductive and pregnancy health histories when assessing the "four great neonatal neurological syndromes". This maternal-child dyad exemplifies the symptomatic neonatal minority, compared with the silent majority of healthy children who experience preclinical diseases with variable expressions over the first 1000 days. Healthy maternal reports with reassuring fetal surveillance testing preceded signs of fetal distress during parturition. An encephalopathic neonate with seizures later exhibited childhood autistic spectrum behaviors and intractable epilepsy correlated with identified genetic biomarkers. A systems biology approach to etiopathogenesis guides the diagnostic process to interpret phenotypic form and function. Evolving gene-environment interactions expressed by changing phenotypes reflect a dynamic neural exposome influenced by reproductive and pregnancy health. This strategy considers critical/sensitive periods of neuroplasticity beyond two years of life to encompass childhood and adolescence. Career-long FNN experiences reenforce earlier training to strengthen the cognitive process and minimize cognitive biases when assessing children or adults. Prioritizing social determinants of healthcare for persons with neurologic disorders will help mitigate the global burden of brain diseases for all women and children.

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

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

Accounting for Nulliparity in the Prediction of Hypoxic-Ischemic Encephalopathy Using Cardiotocography

Nulliparous pregnancies, those where the mother has not previously given birth, are associated with longer labors and hence expose the fetus to more contractions and other adverse intrapartum conditions such as chorioamnionitis. The objective of the present study was to test if accounting for nulliparity could improve the detection of fetuses at increased risk of developing hypoxic-ischemic encephalopathy (HIE). During labor, clinicians assess the fetal heart rate and uterine pressure signals to identify fetuses at risk of developing HIE. In this study, we performed random forest classification using fetal heart rate and uterine pressure features from 40,831 births, including 374 that developed HIE. We analyzed a two-path classification approach that analyzed separately the fetuses from nulliparous and multiparous mothers, and a one-path classification approach that included the clinical variable for nulliparity as a classification feature. We compared these two approaches to a one-path classifier that had no information about the parity of the mothers. We also compared our results to the rate of Caesarean deliveries in each group, which is used clinically to interrupt the progression towards HIE. All the classifiers detected more fetuses that developed HIE than the observed Caesarean rate, but accounting for nulliparity did not improve performance.

Prediction of Fetal Blood Pressure during Labour with Deep Learning Techniques

Our objective is to develop a model for the prediction of minimum fetal blood pressure (FBP) during fetal heart rate (FHR) decelerations. Experimental data from umbilical occlusions in near-term fetal sheep (2698 occlusions from 57 near-term lambs) were used to train a convolutional neural network. This model was then used to estimate FBP for decelerations extracted from the final 90 min of 53,445 human FHR signals collected using cardiotocography. Minimum sheep FBP was predicted with a mean absolute error of 6.7 mmHg (25th, 50th, 75th percentiles of 2.3, 5.2, 9.7 mmHg), mean absolute percentage errors of 17.3% (5.5%, 12.5%, 23.9%) and a coefficient of determination R2=0.36. While the model was unable to clearly predict severe compromise at birth in humans, there is positive evidence that such a model could predict human FBP with further development. The neural network is capable of predicting FBP for many of the sheep decelerations accurately but performed far from satisfactory at identifying FHR segments that correspond to the highest or lowest minimum FBP. These results indicate that with further work and a larger, more variable training dataset, the model could achieve higher accuracy.

Pathophysiological interpretation of fetal heart rate tracings in clinical practice

The onset of regular, strong, and progressive uterine contractions may result in both mechanical (compression of the fetal head and/or umbilical cord) and hypoxic (repetitive and sustained compression of the umbilical cord or reduction in uteroplacental oxygenation) stresses to a human fetus. Most fetuses are able to mount effective compensatory responses to avoid hypoxic-ischemic encephalopathy and perinatal death secondary to the onset of anaerobic metabolism within the myocardium, culminating in myocardial lactic acidosis. In addition, the presence of fetal hemoglobin, which has a higher affinity for oxygen even at low partial pressures of oxygen than the adult hemoglobin, especially increased amounts of fetal hemoglobin (ie, 180-220 g/L in fetuses vs 110-140 g/L in adults), helps the fetus to withstand hypoxic stresses during labor. Different national and international guidelines are currently being used for intrapartum fetal heart rate interpretation. These traditional classification systems for fetal heart rate interpretation during labor are based on grouping certain features of fetal heart rate (ie, baseline fetal heart rate, baseline variability, accelerations, and decelerations) into different categories (eg, category I, II, and III tracings, "normal, suspicious, and pathologic" or "normal, intermediary, and abnormal"). These guidelines differ from each other because of the features included within different categories and because of their arbitrary time limits stipulated for each feature to warrant an obstetrical intervention. This approach fails to individualize care because the "ranges of normality" for stipulated parameters apply to the population of human fetuses and not to the individual fetus in question. Moreover, different fetuses have different reserves and compensatory responses and different intrauterine environments (presence of meconium staining of amniotic fluid, intrauterine inflammation, and the nature of uterine activity). Pathophysiological interpretation of fetal heart rate tracing is based on the application of the knowledge of fetal responses to intrapartum mechanical and/or hypoxic stress in clinical practice. Both experimental animal studies and observational human studies suggest that, just like adults undertaking a treadmill exercise, human fetuses show predictable compensatory responses to a progressively evolving intrapartum hypoxic stress. These responses include the onset of decelerations to reduce myocardial workload and preserve aerobic metabolism, loss of accelerations to abolish nonessential somatic body movements, and catecholamine-mediated increases in the baseline fetal heart rate and effective redistribution and centralization to protect the fetal central organs (ie, the heart, brain, and adrenal glands), which are essential for intrauterine survival. Moreover, it is essential to incorporate the clinical context (progress of labor, fetal size and reserves, presence of meconium staining of amniotic fluid and intrauterine inflammation, and fetal anemia) and understand the features suggestive of fetal compromise in nonhypoxic pathways (eg, chorioamnionitis and fetomaternal hemorrhage). It is important to appreciate that the timely recognition of the speed of onset of intrapartum hypoxia (ie, acute, subacute, and gradually evolving) and preexisting uteroplacental insufficiency (ie, chronic hypoxia) on fetal heart rate tracing is crucial to improve perinatal outcomes.

Continuous fetal cerebral blood flow monitoring during labor: A feasibility study

BACKGROUND

Current methods for fetal surveillance during labor have significant limitations. Since continuous fetal cerebral blood flow velocity (CBFV) monitoring during labor may add valuable information about fetal well-being, we developed a new ultrasound system called VisiBeam. VisiBeam consists of a flat probe (diameter 11 mm) with a cylindric plane wave beam, a vacuum attachment (diameter 40 mm), a scanner, and a display.

AIMS

To assess the feasibility of VisiBeam for continuous fetal CBFV monitoring during labor, and to study changes in CBFV during uterine contractions.

STUDY DESIGN

Descriptive observational study.

SUBJECTS

Twenty-five healthy women in labor with a singleton fetus in cephalic presentation at term. A transducer was placed over a fontanelle and attached to the fetal head with vacuum suction.

OUTCOME MEASURES

Achievement of continuous good quality fetal CBFV measures, such as peak systolic velocity, time averaged maximum velocity and end diastolic velocity. Trend plots of velocity measures display changes in CBFV between and during uterine contractions.

RESULTS

Good quality recordings during and between contractions were achieved in 16/25 fetuses. In twelve fetuses, CBFV measures were stable during uterine contractions. Four fetuses showed patterns of reduced CBFV velocity measures during contractions.

CONCLUSIONS

Continuous fetal CBFV monitoring by VisiBeam was feasible in 64 % of the subjects during labor. The system displayed variations of fetal CBFV not available by today's monitoring techniques and motivates for further studies. However, improvement of the probe attachment is required to ensure good quality signal in a higher proportion of fetuses during labor.

Vitality in Newborn Farm Animals: Adverse Factors, Physiological Responses, Pharmacological Therapies, and Physical Methods to Increase Neonate Vigor

Vitality is the vigor newborn animals exhibit during the first hours of life. It can be assessed by a numerical score, in which variables, such as heart rate, respiratory rate, mucous membranes' coloration, time the offspring took to stand up, and meconium staining, are monitored. Vitality can be affected by several factors, and therapies are used to increase it. This manuscript aims to review and analyze pharmacological and physical therapies used to increase vitality in newborn farm animals, as well as to understand the factors affecting this vitality, such as hypoxia, depletion of glycogen, birth weight, dystocia, neurodevelopment, hypothermia, and finally, the physiological mechanism to achieve thermostability. It has been concluded that assessing vitality immediately after birth is essential to determine the newborn's health and identify those that need medical intervention to minimize the deleterious effect of intrapartum asphyxia. Vitality assessment should be conducted by trained personnel and adequate equipment. Evaluating vitality could reduce long-term neonatal morbidity and mortality in domestic animals, even if it is sometimes difficult with the current organization of some farms. This review highlights the importance of increasing the number of stock people during the expected days of parturitions to reduce long-term neonatal morbidity and mortality, and thus, improve the farm's performance.

Fetal defenses against intrapartum head compression-implications for intrapartum decelerations and hypoxic-ischemic injury

Uterine contractions during labor and engagement of the fetus in the birth canal can compress the fetal head. Its impact on the fetus is unclear and still controversial. In this integrative physiological review, we highlight evidence that decelerations are uncommonly associated with fetal head compression. Next, the fetus has an impressive ability to adapt to increased intracranial pressure through activation of the intracranial baroreflex, such that fetal cerebral perfusion is well-maintained during labor, except in the setting of prolonged systemic hypoxemia leading to secondary cardiovascular compromise. Thus, when it occurs, fetal head compression is not necessarily benign but does not seem to be a common contributor to intrapartum decelerations. Finally, the intracranial baroreflex and the peripheral chemoreflex (the response to acute hypoxemia) have overlapping efferent effects. We propose the hypothesis that these reflexes may work synergistically to promote fetal adaptation to labor.

Dissecting the contributions of the peripheral chemoreflex and myocardial hypoxia to fetal heart rate decelerations in near-term fetal sheep

Brief repeated fetal hypoxaemia during labour can trigger intrapartum decelerations of the fetal heart rate (FHR) via the peripheral chemoreflex or the direct effects of myocardial hypoxia, but the relative contribution of these two mechanisms and how this balance changes with evolving fetal compromise remain unknown. In the present study, chronically instrumented near-term fetal sheep received surgical vagotomy (n = 8) or sham vagotomy (control, n = 11) to disable the peripheral chemoreflex and unmask myocardial hypoxia. One-minute complete umbilical cord occlusions (UCOs) were performed every 2.5 min for 4 h or until arterial pressure fell below 20 mmHg. Hypotension and severe acidaemia developed progressively after 65.7 ± 7.2 UCOs in control fetuses and 49.5 ± 7.8 UCOs after vagotomy. Vagotomy was associated with faster development of metabolic acidaemia and faster impairment of arterial pressure during UCOs without impairing centralization of blood flow or neurophysiological adaptation to UCOs. During the first half of the UCO series, before severe hypotension developed, vagotomy was associated with a marked increase in FHR during UCOs. After the onset of evolving severe hypotension, FHR fell faster in control fetuses during the first 20 s of UCOs, but FHR during the final 40 s of UCOs became progressively more similar between groups, with no difference in the nadir of decelerations. In conclusion, FHR decelerations were initiated and sustained by the peripheral chemoreflex at a time when fetuses were able to maintain arterial pressure. After the onset of evolving hypotension and acidaemia, the peripheral chemoreflex continued to initiate decelerations, but myocardial hypoxia became progressively more important in sustaining and deepening decelerations. KEY POINTS: Brief repeated hypoxaemia during labour can trigger fetal heart rate decelerations by either the peripheral chemoreflex or myocardial hypoxia, but how this balance changes with fetal compromise is unknown. Reflex control of fetal heart rate was disabled by vagotomy to unmask the effects of myocardial hypoxia in chronically instrumented fetal sheep. Fetuses were then subjected to repeated brief hypoxaemia consistent with the rates of uterine contractions during labour. We show that the peripheral chemoreflex controls brief decelerations in their entirety at a time when fetuses were able to maintain normal or increased arterial pressure. The peripheral chemoreflex still initiated decelerations even after the onset of evolving hypotension and acidaemia, but myocardial hypoxia made an increasing contribution to sustain and deepen decelerations.

Foetal Intrapartum Compromise at Term: Could COVID-19 Infection Be Involved? A Case Report

The impact of the SARS-CoV-2 infection on pregnancy has been studied and many reports have been published, mainly focussing on complications and in utero transmission with neonatal consequences. Although the effects of other viruses on foetuses are well known, the impact of maternal COVID-19 during pregnancy is not completely understood. We report a case of acute foetal intrapartum hypoxia without other risk factors than maternal COVID-19 disease 2 weeks previous to birth at term. Placental histological changes suggested that the viral infection could have been the culprit for the unfavourable outcome during labour. The neonate was promptly delivered by Caesarean section. Neonatal intensive care was started, including therapeutic hypothermia. The procedure was successful, the evolution of the neonate was favourable, and she was discharged after 10 days. Follow-up at 2 months of life indicated a normal neurological development but a drop in head growth. The case raises the idea that pregnancies with even mild COVID-19 symptoms may represent the cause of neonate compromise in a low-risk pregnancy. An important follow-up in the neonatal period and infancy is required to identify and treat any subsequent conditions. Further long-term studies are necessary to identify a cause–effect relationship between COVID-19 pregnancies and the whole spectrum of neonatal and infant consequences.

Maternal and newborn plasma oxytocin levels in response to maternal synthetic oxytocin administration during labour, birth and postpartum - a systematic review with implications for the function of the oxytocinergic system

BACKGROUND

The reproductive hormone oxytocin facilitates labour, birth and postpartum adaptations for women and newborns. Synthetic oxytocin is commonly given to induce or augment labour and to decrease postpartum bleeding.

AIM

To systematically review studies measuring plasma oxytocin levels in women and newborns following maternal administration of synthetic oxytocin during labour, birth and/or postpartum and to consider possible impacts on endogenous oxytocin and related systems.

METHODS

Systematic searches of PubMed, CINAHL, PsycInfo and Scopus databases followed PRISMA guidelines, including all peer-reviewed studies in languages understood by the authors. Thirty-five publications met inclusion criteria, including 1373 women and 148 newborns. Studies varied substantially in design and methodology, so classical meta-analysis was not possible. Therefore, results were categorized, analysed and summarised in text and tables.

RESULTS

Infusions of synthetic oxytocin increased maternal plasma oxytocin levels dose-dependently; doubling the infusion rate approximately doubled oxytocin levels. Infusions below 10 milliunits per minute (mU/min) did not raise maternal oxytocin above the range observed in physiological labour. At high intrapartum infusion rates (up to 32 mU/min) maternal plasma oxytocin reached 2-3 times physiological levels. Postpartum synthetic oxytocin regimens used comparatively higher doses with shorter duration compared to labour, giving greater but transient maternal oxytocin elevations. Total postpartum dose was comparable to total intrapartum dose following vaginal birth, but post-caesarean dosages were higher. Newborn oxytocin levels were higher in the umbilical artery vs. umbilical vein, and both were higher than maternal plasma levels, implying substantial fetal oxytocin production in labour. Newborn oxytocin levels were not further elevated following maternal intrapartum synthetic oxytocin, suggesting that synthetic oxytocin at clinical doses does not cross from mother to fetus.

CONCLUSIONS

Synthetic oxytocin infusion during labour increased maternal plasma oxytocin levels 2-3-fold at the highest doses and was not associated with neonatal plasma oxytocin elevations. Therefore, direct effects from synthetic oxytocin transfer to maternal brain or fetus are unlikely. However, infusions of synthetic oxytocin in labour change uterine contraction patterns. This may influence uterine blood flow and maternal autonomic nervous system activity, potentially harming the fetus and increasing maternal pain and stress.

Fetal heart rate responses in chronic hypoxaemia with superimposed repeated hypoxaemia consistent with early labour: a controlled study in fetal sheep

OBJECTIVE

Deceleration area (DA) and capacity (DC) of the fetal heart rate can help predict risk of intrapartum fetal compromise. However, their predictive value in higher risk pregnancies is unclear. We investigated whether they can predict the onset of hypotension during brief hypoxaemia repeated at a rate consistent with early labour in fetal sheep with pre-existing hypoxaemia.

DESIGN

Prospective, controlled study.

SETTING

Laboratory.

SAMPLE

Chronically instrumented, unanaesthetised near-term fetal sheep.

METHODS

One-minute complete umbilical cord occlusions (UCOs) were performed every 5 minutes in fetal sheep with baseline p_a O₂ <17 mmHg (hypoxaemic, n = 8) and >17 mmHg (normoxic, n = 11) for 4 hours or until arterial pressure fell <20 mmHg.

MAIN OUTCOME MEASURES

DA, DC and arterial pressure.

RESULTS

Normoxic fetuses showed effective cardiovascular adaptation without hypotension and mild acidaemia (lowest arterial pressure 40.7 ± 2.8 mmHg, pH 7.35 ± 0.03). Hypoxaemic fetuses developed hypotension (lowest arterial pressure 20.8 ± 1.9 mmHg, P < 0.001) and acidaemia (final pH 7.07 ± 0.05). In hypoxaemic fetuses, decelerations showed faster falls in FHR over the first 40 seconds of UCOs but the final deceleration depth was not different to normoxic fetuses. DC was modestly higher in hypoxaemic fetuses during the penultimate (P = 0.04) and final (P = 0.012) 20 minutes of UCOs. DA was not different between groups.

CONCLUSION

Chronically hypoxaemic fetuses had early onset of cardiovascular compromise during labour-like brief repeated UCOs. DA was unable to identify developing hypotension in this setting, while DC only showed modest differences between groups. These findings highlight that DA and DC thresholds need to be adjusted for antenatal risk factors, potentially limiting their clinical utility.

A second look at intrapartum fetal surveillance and future directions

Intrapartum fetal surveillance aims to predict significant fetal hypoxia and institute timely intervention to avoid fetal injury, and do so without unnecessary operative delivery of fetuses at no risk of intrapartum hypoxia. However, the configuration and application of current clinical guidelines inadvertently undermine these aims because of persistent failure to incorporate increased understanding of fetal cardiovascular physiology and adaptations to oxygen deprivation, advances in signal acquisition/processing, and related technologies. Consequently, the field on intrapartum fetal surveillance is stuck in rudimentary counts of the fetal R-R intervals and visual assessment of very common, but nonspecific fetal heart decelerations and fetal heart rate variability. The present authors argue that the time has come to move away from classifications of static morphological appearances of FHR decelerations, which do not assist the thinking clinician in understanding how the fetus defends itself and compensates for intrapartum hypoxic ischaemic insults or the patterns that suggest progressive loss of compensation. We also reappraise some of the controversial aspects of intrapartum fetal surveillance in modern obstetric practice, the current state of flux in training and certification, and contemplate the future of the field particularly in the context of the emerging role of artificial intelligence.

Predelivery placenta-associated biomarkers and computerized intrapartum fetal heart rate patterns

Background

Increasing syncytiotrophoblast stress in term and postdate placentas is reflected by increasing antiangiogenic dysregulation in the maternal circulation, with low "proangiogenic" placental growth factor concentrations and increased "antiangiogenic" soluble fms-like tyrosine kinase-1 concentrations. Imbalances in these placenta-associated proteins are associated with intrapartum fetal compromise and adverse pregnancy and delivery outcome. Cardiotocography is widely used to assess fetal well-being during labor, but it is insufficient on its own for predicting adverse neonatal outcome. Development of improved surveillance tools to detect intrapartum fetal stress are needed to prevent neonatal adverse outcome.

Objective

This study aimed to assess whether predelivery circulating maternal angiogenic protein concentrations are associated with intrapartum computerized fetal heart rate patterns, as calculated by the Oxford System for computerized intrapartum monitoring (OxSys) 1.7 prototype. We hypothesized that in pregnancies with low "proangiogenic" placental growth factor levels, increased "antiangiogenic" soluble fms-like tyrosine kinase-1 levels, and increased soluble fms-like tyrosine kinase-1-placental growth factor ratio, the OxSys 1.7 prototype will generate more automated alerts, indicating fetal compromise. Our secondary objective was to investigate the relationship between maternal circulating placenta-associated biomarkers and rates of automated alerts in pregnancies with and without adverse neonatal outcome.

Study Design

This was an observational prospective cohort study conducted at a single tertiary center from September 2016 to March 2020. Of 1107 singleton pregnancies (gestational week ≥37⁺⁰), 956 had available prelabor and predelivery placental growth factor and soluble fms-like tyrosine kinase-1 concentrations and intrapartum cardiotocography recordings. All neonatal and delivery outcomes were externally reviewed and categorized into 2 groups-the "complicated" group (n=32) and the "uncomplicated" group (n=924)-according to predefined adverse neonatal outcome. Eight different cardiotocography features were calculated by OxSys 1.7: baseline at start of cardiotocography, baseline at end of cardiotocography, short-term variation at start, short-term variation at end, nonreactive initial trace, and throughout the entire cardiotocography, maximum decelerative capacity, total number of prolonged decelerations, and OxSys 1.7 alert. OxSys 1.7 triggered an alert if the initial trace was nonreactive or if decelerative capacity and/or the number of prolonged decelerations exceeded a predefined threshold. Included women and attending clinicians were blinded to both biomarker and OxSys 1.7 results.

Results

Mean maternal placental growth factor concentration was lower in the group with OxSys 1.7 alert compared with the group without the alert (151 vs 169 pg/mL; P=.04). There was a weak negative correlation between predelivery high soluble fms-like tyrosine kinase-1 and low short-term variation start (r _s=-0.068; 95% confidence interval, -0.131 to -0.004; P=.036), predelivery high soluble fms-like tyrosine kinase-1 and low short-term variation end (r _s=-0.068; 95% confidence interval, -0.131 to -0.005; P=.036), and high soluble fms-like tyrosine kinase-1-placental growth factor ratio and low short-term variation end (r _s=-0.071; 95% confidence interval, -0.134 to -0.008; P=.027). The rate of decelerative capacity alerts increased more rapidly as placental growth factor decreased in the "complicated" compared with the "uncomplicated" group (0% to 17% vs 4% to 8%).

Conclusion

More automated alerts indicative of fetal distress were generated by OxSys 1.7 in pregnancies with low maternal predelivery placental growth factor level, in line with likely increasing placental stress toward the end of the pregnancy. An antiangiogenic predelivery profile (lower placental growth factor) increased the rates of alerts more rapidly in pregnancies with adverse neonatal outcome compared with those without. We suggest that future studies developing and testing prediction tools for intrapartum fetal compromise include predelivery maternal placental growth factor measurements.

Increased variability of fetal heart rate during labour: a review of preclinical and clinical studies

Increased fetal heart rate variability (FHRV) in intrapartum cardiotocographic recording has been variably defined and poorly understood, limiting its clinical utility. Both preclinical (animal) and clinical (human) evidence support that increased FHRV is observed in the early stage of intrapartum fetal hypoxaemia but can also be observed in a subset of fetuses during the preterminal stage of repeated hypoxaemia. This review of available evidence provides data and expert opinion on the pathophysiology of increased FHRV, its clinical significance and a stepwise approach regarding the management of this pattern, and propose recommendations for standardisation of related terminology.

Is It Time to Redefine Fetal Decelerations in Cardiotocography?

Historically, fetal heart rate (FHR) decelerations were classified into “early”, “late”, and “variable” based on their relationship with uterine contractions. So far, three different putative etiologies were taken for granted. Recently, this belief, passed down through generations of birth attendants, has been questioned by physiologists. This narrative review aimed to assess the evidence on pathophysiology behind intrapartum FHR decelerations. This narrative review is based on information sourced from online peer-reviewed articles databases and recommendations from the major scientific societies in the field of obstetrics. Searches were performed in MEDLINE/PubMed, EMBASE, and Scopus and selection criteria included studies in animals and humans, where the physiology behind FHR decelerations was explored. The greater affinity for oxygen of fetal hemoglobin than the maternal, the unicity of fetal circulation, and the high anaerobic reserve of the myocardium, ensure adequate oxygenation to the fetus, under basal conditions. During acute hypoxic stress the efficiency of these mechanisms are increased because of the peripheral chemoreflex. This reflex, activated at each uterine contraction, is characterized by the simultaneous activation of two neural arms: the parasympathetic arm, which reduces the myocardial consumption of oxygen by decreasing the FHR and the sympathetic component, which promotes an intense peripheric vasoconstriction, thus centralizing the fetal blood volume. This review summarizes the evidence supporting the hypoxic origin of FHR decelerations, therefore archiving the historical belief that FHR decelerations have different etiologies, according to their shape and relationship with uterine contractions. The present review suggests that it is time to welcome the new scientific evidence and to update the CTG classification systems.

The Nonlinear Dynamic Response of Intrapartum Fetal Heart Rate to Uterine Pressure

The research objective of our group is to improve the intrapartum detection of cardiotocography tracings associated with an increased risk of developing fetal acidosis and subsequent hypoxic-ischemic encephalopathy (HIE). The detection methods that we aim to develop must be sensitive to abnormal tracings without causing excessive unnecessary interventions. Past studies showed that the dynamic response of fetal heart rate (FHR) to uterine pressure (UP) during the intrapartum could be modelled using linear systems. In this study, we examined the assumption of linearity by comparing the performance of linear dynamic and nonlinear dynamic models of the UP-FHR system. The linear systems were defined by second-order state-space models. The nonlinear systems were defined by Hammerstein models: a cascade of a static nonlinearity and a linear second-order state-space model. Our results showed that nonlinear dynamic models were better than linear systems in 81.8% of UP-FHR segments.

Gene-Environment Interactions During the First Thousand Days Influence Childhood Neurological Diagnosis

Gene-environment (G x E) interactions significantly influence neurologic outcomes. The maternal-placental-fetal (MPF) triad, neonate, or child less than 2 years may first exhibit significant brain disorders. Neuroplasticity during the first 1000 days will more likely result in life-long effects given critical periods of development. Developmental origins and life-course principles help recognize changing neurologic phenotypes across ages. Dual diagnostic approaches are discussed using representative case scenarios to highlight time-dependent G x E interactions that contribute to neurologic sequelae. Horizontal analyses identify clinically relevant phenotypic form and function at different ages. Vertical analyses integrate the approach using systems-biology from genetic through multi-organ system interactions during each developmental age to understand etiopathogenesis. The process of ontogenetic adaptation results in immediate or delayed positive and negative outcomes specific to the developmental niche, expressed either as a healthy child or one with neurologic sequelae. Maternal immune activation, ischemic placental disease, and fetal inflammatory response represent prenatal disease pathways that contribute to fetal brain injuries. These processes involve G x E interactions within the MPF triad, phenotypically expressed as fetal brain malformations or destructive injuries within the MPF triad. A neonatal minority express encephalopathy, seizures, stroke, and encephalopathy of prematurity as a continuum of trimester-specific G x E interactions. This group may later present with childhood sequelae. A healthy neonatal majority present at older ages with sequelae such as developmental disorders, epilepsy, mental health diseases, tumors, and neurodegenerative disease, often during the first 1000 days. Effective preventive, rescue, and reparative neuroprotective strategies require consideration of G x E interactions interplay over time. Addressing maternal and pediatric health disparities will maximize medical equity with positive global outcomes that reduce the burden of neurologic diseases across the lifespan.

Multi-Chain Semi-Markov Analysis of Intrapartum Cardiotocography

Visual assessment of the evolution of fetal heart rate (FHR) and uterine pressure (UP) patterns is the standard of care in the intrapartum period. Unfortunately, this assessment has high levels of intra- and inter-observer variability. This study processed and analyzed FHR and UP patterns using computerized pattern recognition tools. The goal was to evaluate differences in FHR and UP patterns between fetuses with normal outcomes and those who developed hypoxic-ischemic encephalopathy (HIE). For this purpose, we modeled the sequence of FHR patterns and uterine contractions using Multi-Chain Semi-Markov models (MCSMMs). These models estimate the probability of transitioning between FHR or UP patterns and the dwell time of each pattern. Our results showed that in comparison to the control group, the HIE group had: (1) more frequent uterine contractions during the last 12 hours before birth; (2) more frequent FHR decelerations during the last 12 hours before birth; (3) longer decelerations during the last eight hours before birth; and (4) shorter baseline durations during the last five hours before birth. These results demonstrate that the fetuses in the HIE group were subject to a more stressful environment than those in the normal group. Clinical Relevance- Our results revealed statistically significant differences in FHR/UP patterns between the normal and HIE groups in the hours before birth. This indicates that features derived using MCSMMs may be useful in a machine learning framework to detect infants at increased risk of developing HIE allowing preventive interventions.

Sodium dichloroacetate stimulates cardiac mitochondrial metabolism and improves cardiac conduction in the ovine fetus during labor

Previous studies in our laboratory have suggested that the increase in stillbirth in pregnancies complicated by chronic maternal stress or hypercortisolemia is associated with cardiac dysfunction in late stages of labor and delivery. Transcriptomics analysis of the overly represented differentially expressed genes in the fetal heart of hypercortisolemic ewes indicated involvement of mitochondrial function. Sodium dichloroacetate (DCA) has been used to improve mitochondrial function in several disease states. We hypothesized that administration of DCA to laboring ewes would improve both cardiac mitochondrial activity and cardiac function in their fetuses. Four groups of ewes and their fetuses were studied: control, cortisol-infused (1 g/kg/day from 115 to term; CORT), DCA-treated (over 24 h), and DCA + CORT-treated; oxytocin was delivered starting 48 h before the DCA treatment. DCA significantly decreased cardiac lactate, alanine, and glucose/glucose-6-phosphate and increased acetylcarnitine/isobutyryl-carnitine. DCA increased mitochondrial activity, increasing oxidative phosphorylation (P_CI, P_CI + II) per tissue weight or per unit of citrate synthase. DCA also decreased the duration of the QRS, attenuating the prolongation of the QRS observed in CORT fetuses. The effect to reduce QRS duration with DCA treatment correlated with increased glycerophosphocholine and serine and decreased phosphorylcholine after DCA treatment. There were negative correlations of acetylcarnitine/isobutyryl-carnitine to both heart rate (HR) and mean arterial pressure (MAP). These results suggest that improvements in mitochondrial respiration with DCA produced changes in the cardiac lipid metabolism that favor improved conduction in the heart. DCA may therefore be an effective treatment of fetal cardiac metabolic disturbances in labor that can contribute to impairments of fetal cardiac conduction.

Machine Learning Algorithm to Predict Acidemia Using Electronic Fetal Monitoring Recording Parameters

Background: Electronic fetal monitoring (EFM) is the universal method for the surveillance of fetal well-being in intrapartum. Our objective was to predict acidemia from fetal heart signal features using machine learning algorithms. Methods: A case–control 1:2 study was carried out compromising 378 infants, born in the Miguel Servet University Hospital, Spain. Neonatal acidemia was defined as pH < 7.10. Using EFM recording logistic regression, random forest and neural networks models were built to predict acidemia. Validation of models was performed by means of discrimination, calibration, and clinical utility. Results: Best performance was attained using a random forest model built with 100 trees. The discrimination ability was good, with an area under the Receiver Operating Characteristic curve (AUC) of 0.865. The calibration showed a slight overestimation of acidemia occurrence for probabilities above 0.4. The clinical utility showed that for 33% cutoff point, missing 5% of acidotic cases, 46% of unnecessary cesarean sections could be prevented. Logistic regression and neural networks showed similar discrimination ability but with worse calibration and clinical utility. Conclusions: The combination of the variables extracted from EFM recording provided a predictive model of acidemia that showed good accuracy and provides a practical tool to prevent unnecessary cesarean sections.

Physiological control of fetal heart rate variability during labour: Implications and controversies

The interpretation of fetal heart rate (FHR) patterns is the only available method to continuously monitor fetal wellbeing during labour. One of the most important yet contentious aspects of the FHR pattern is changes in FHR variability (FHRV). Some clinical studies suggest that loss of FHRV during labour is a sign of fetal compromise so this is reflected in practice guidelines. Surprisingly, there is little systematic evidence to support this observation. In this review we methodically dissect the potential pathways controlling FHRV during labour-like hypoxaemia. Before labour, FHRV is controlled by the combined activity of the parasympathetic and sympathetic nervous systems, in part regulated by a complex interplay between fetal sleep state and behaviour. By contrast, preclinical studies using multiple autonomic blockades have now shown that sympathetic neural control of FHRV was potently suppressed between periods of labour-like hypoxaemia, and thus, that the parasympathetic system is the sole neural regulator of FHRV once FHR decelerations are present during labour. We further discuss the pattern of changes in FHRV during progressive fetal compromise and highlight potential biochemical, behavioural and clinical factors that may regulate parasympathetic-mediated FHRV during labour. Further studies are needed to investigate the regulators of parasympathetic activity to better understand the dynamic changes in FHRV and their true utility during labour. This article is protected by copyright. All rights reserved.

Analysis of Maternal and Neonatal Complications in a Group of Patients with Gestational Diabetes Mellitus

Background and Objectives: Gestational diabetes mellitus (GDM) represents one of the most common complications during pregnancy, being associated with numerous maternal and neonatal complications. The study aimed to analyze maternal and neonatal complications associated with GDM. The risk factors of GDM and of the maternal and neonatal complications were studied in order to prevent their occurrence. Materials and Methods: The study included 97 women in the study, who underwent an oral glucose tolerance test (OGTT) between weeks 24–28 of pregnancy, consequently being divided into two groups: pregnant women with and without GDM. Statistical analysis was performed using the SPSS 26.0 software and MATLAB fitglm, the results being considered statistically significant if p < 0.05. Results: We observed statistically significant differences between the group of women with and without GDM, regarding gestational hypertension (17.6% vs. 0%), preeclampsia (13.72% vs. 0%), and cesarean delivery (96.1% vs. 78,3%). Data on the newborn and neonatal complications: statistically significant differences were recorded between the two groups (GDM vs. no GDM) regarding the average weight at birth (3339.41 ± 658.12 g vs. 3122.83 ± 173.67 g), presence of large for gestational age (21.6% vs. 0%), macrosomia (13.7% vs. 0%), excessive fetal growth (35.3% vs. 0%), respiratory distress (31.4% vs. 0%), hospitalization for at least 24 h in the Neonatal Intensive Care Unit (9.80% vs. 0%), and APGAR score <7 both 1 and 5 min following birth (7.8% vs. 0%). Additionally, the frequency of neonatal hypoglycemia and hyperbilirubinemia was higher among newborns from mothers with GDM. Conclusions: The screening and diagnosis of GDM is vital, and appropriate management is required for the prevention of maternal and neonatal complications associated with GDM. It is also important to know the risk factors for GDM and attempt to prevent their appearance.

Neurologic Sequelae Associated with Hypertensive Disorders of Pregnancy

Hypertensive disorders of pregnancy (HDP) contribute to adverse gene-environment interactions prior to conception and continue throughout pregnancy. Embryonic/fetal brain disorders occur from interactions between genetic susceptibilities interacting with acquired diseases or conditions affecting the maternal/placental fetal (MPF) triad. Trimester-specific pathophysiological mechanisms, such as maternal immune activation and ischemic placental syndrome, contribute to adverse peripartum, neonatal and childhood outcomes. Two diagnostic approaches provide timelier diagnoses over the first 1000 days from conception until two years of age. Horizontal analyses assess the maturation of the triad, neonate and child. Vertical analyses consider systems-biology from genetic, molecular, cellular, tissue through organ networks during each developmental niche. Disease expressions associated with HDP have cumulative adverse effects across the lifespan when subjected to subsequent adverse events. Critical/sensitive periods of developmental neuroplasticity over the first 1000 days are more likely to result in permanent sequelae. Novel diagnostic approaches, beginning during pre-conception, will facilitate the development of effective preventive, rescue and reparative neurotherapeutic strategies in response to HDP-related trimester-specific disease pathways. Public health policies require the inclusion of women's health advocacy during and beyond their reproductive years to reduce sequelae experienced by mothers and their offspring. A lower global burden of neurologic disease from HDP will benefit future generations.

Cerebral hemodynamics during neonatal transition according to mode of delivery

Cerebral haemodynamics during the immediate transition period in neonates may differ depending on whether delivery is vaginal or by caesarean section. However, these differences have never been confirmed by near-infrared time-resolved spectroscopy (TRS). Therefore, the purpose of this study was to compare cerebral blood volume (CBV) and cerebral haemoglobin oxygen saturation (ScO₂) between healthy term neonates by mode of delivery. Subjects were 31 healthy term neonates who did not require resuscitation. Thirteen neonates were delivered vaginally (VD group) and 18 were delivered by elective caesarean section (CS group). Absolute oxyhaemoglobin, deoxyhaemoglobin, and total haemoglobin concentrations were measured continuously by TRS; oxyHb × 100/totalHb (ScO₂) (%) and CBV (mL/100 g brain tissue) were also calculated. Measurements were started as soon as possible after birth, obtained from 1 to 2 min after birth, and continued until 15 min after birth. CBV was significantly higher in the VD group than in the CS group in the 4 min after birth but not thereafter. There were no significant between-group differences in ScO₂ and SpO₂. These findings indicate that there is a difference in cerebral haemodynamic patterns in the first 4 min after delivery between term neonates by mode of delivery when CBV is monitored by TRS.

Estimation and Discriminability of Doppler Ultrasound Fetal Heart Rate Variability Measures

Continuous electronic fetal monitoring and the access to databases of fetal heart rate (FHR) data have sparked the application of machine learning classifiers to identify fetal pathologies. However, most fetal heart rate data are acquired using Doppler ultrasound (DUS). DUS signals use autocorrelation (AC) to estimate the average heartbeat period within a window. In consequence, DUS FHR signals loses high frequency information to an extent that depends on the length of the AC window. We examined the effect of this on the estimation bias and discriminability of frequency domain features: low frequency power (LF: 0.03–0.15 Hz), movement frequency power (MF: 0.15–0.5 Hz), high frequency power (HF: 0.5–1 Hz), the LF/(MF + HF) ratio, and the nonlinear approximate entropy (ApEn) as a function of AC window length and signal to noise ratio. We found that the average discriminability loss across all evaluated AC window lengths and SNRs was 10.99% for LF 14.23% for MF, 13.33% for the HF, 10.39% for the LF/(MF + HF) ratio, and 24.17% for ApEn. This indicates that the frequency domain features are more robust to the AC method and additive noise than the ApEn. This is likely because additive noise increases the irregularity of the signals, which results in an overestimation of ApEn. In conclusion, our study found that the LF features are the most robust to the effects of the AC method and noise. Future studies should investigate the effect of other variables such as signal drop, gestational age, and the length of the analysis window on the estimation of fHRV features and their discriminability.

Prelabor and intrapartum Doppler ultrasound to predict fetal compromise

According to current estimates, over 20% of the 4 million neonatal deaths occurring globally every year are related to intrapartum hypoxic complications that happen as a result of uterine contractions against a background of inadequate placental function. Most of such intrapartum complications occur among apparently uncomplicated term pregnancies. Available evidence suggests that current risk-assessment strategies do not adequately identify many of the fetuses vulnerable to periods of intermittent hypoxia that characterize human labor. In this review, we discuss the data available on Doppler ultrasound for the evaluation of placental function before and during labor in appropriately grown fetuses; we also discuss the current strategies for ultrasound-based risk stratification, the physiology of intrapartum compromise, and the potential future treatments to prevent fetal distress in labor and reduce perinatal complications related to birth asphyxia.

The present and future of intrapartum computerized cardiotocography: role of pattern recognition incorporating single vs. multiple parameters

Computer assisted cardiotocography holds a great promise in minimizing human errors thereby improving perinatal outcome. Despite exponential growth (Moore's law) in computing power for decades, this promise remains unrealized. The systematic analyses of studies on computerized cardiotocography offer little guide to future. This analytical review presents a more qualitative discussion of available evidence as well as concepts regarding the development and acceptance of computerized cardiotocography. To begin with, a workable approach would be for computer algorithms to follow the most scientific visual cardiotocography interpretation frameworks incorporating multiple fetal heart rate parameters and uterine contractions. This ability could be studied and form the basis for regulation of computer algorithms. Addition of background risk factors would be another step. This may take form of familiar multi-tier systems or new alternative strategies like the fetal reserve index. "Machine learning" will remain challenging because of complex variability in fetal-maternal conditions, labor characteristics and clinical intervention changing the outcomes. Randomized controlled trials of adequate size may remain very rare. However, prospective and retrospective testing of computer algorithms with careful qualitative and comparative approach would help clinicians and hospital managers in their decisions. Singular parameters like the popular "deceleration area" and "deceleration capacity" have poor predictive value for fetal acidemia or hypoxic injury. Scientific pattern-recognition of important fetal heart rate parameters like decelerations seems crucial for visual as well as computerized cardiotocography. Success of computerizedcardiotocography depends on team effort by the obstetricians with in-depth practical knowledge/experience and skilled artificial intelligence (AI) specialists.

Roles of parasympathetic outflow and sympathetic outflow in the cardiovascular response to brief umbilical cord occlusion in fetal sheep

Fetal heart rate (FHR) deceleration is the most common change seen during labor. The role of the autonomic nervous system in regulating the fetal cardiovascular response during multiple uterine contractions has been well-established. However, the mechanism underlying the hemodynamic response remains unclear and the specific reflex that mediates the cardiovascular modifications is still controversial. This study aimed to determine the role of the sympathetic and parasympathetic systems on fetal hemodynamics in complete cord occlusion. Chronically instrumented fetal sheep were randomized to receive an intravenous injection of atropine 2.5 mg (n = 8), propranolol 5 mg (n = 7), atropine and propranolol (n = 7), or a control protocol (n = 9), followed by three episodes of 1-minute umbilical cord occlusion repeated every 5 minutes. Cord compression induces a rapid decrease in the FHR and a rapid increase in MAP. The decrease in FHR is caused by an increase in parasympathetic activity, (atropine and atropine-propranolol abolish the FHR response to the occlusion). The change in FHR during occlusion was not modified by propranolol injection, showing no effect of sympathetic tone. The increase in MAP during occlusion was similar in the four protocols. After releasing occlusion, the FHR was still lower than that at baseline due to a sustained parasympathetic tone. Suppression of the parasympathetic output to the cardiovascular system unmasks an increase in the FHR above baseline values. The lower FHR with the propranolol protocol further supports an increase in myocardial β-adrenoceptor stimulation after cord release. The increase in MAP after cord release was similar in the four protocols, except after the early stage of interocclusion period in atropine protocol. Four minutes after cord release, the FHR returned to baseline irrespective of the drugs that were infused, thereby showing recovery of ANS control. Blood gases (pH, PaCO2, PaO2) and plasma lactate concentrations was similar between the four protocols at the end of three applications of UCO. Complete cord compression-induced deceleration is likely due to acute activation of parasympathetic output. β-adrenoceptor activity is involved in the increase in FHR after cord release. Understanding the reflexes involved in FHR deceleration may help us understand the mechanisms underlying fetal autonomic adaptation during cord occlusion.

Changes in S100B and troponin levels in a fetal sheep model of worsening acidosis

BACKGROUND

S100B and cardiac troponin T (c-TnT) are relevant biomarkers at birth of hypoxic-ischemic encephalopathy (HIE) and myocardial ischemia secondary to metabolic acidosis during labor, respectively. The purpose was to assess in-utero changes in S100B and c-TnT levels in an experimental model of labor-like acidosis.

METHODS

Repeated umbilical cord occlusions (UCOs) in ten experiments were performed in mild (phase A, 1 UCO/5 mn), moderate (phase B, 1 UCO/3 mn), and severe (phase C, 1 UCO/2 mn) period. The experiments were stopped if arterial pH reached 6.90.

RESULTS

UCOs resulted in fetal acidosis with pH dropping to 6.99 ±0.13. When compared to the baseline period fetal S100B increased between phases A and B (7% ± 4 vs 17% ± 13, p = 0.030) and between phases A and C (7% ± 4 vs 24% ± 8, p < 0.001). Fetal c-TnT serum levels increased during occlusions: 102 ng/L (58-119) in phase A, vs 119 ng/L (103-198) in phase B vs 169 ng / L (128-268) in phase C (p < 0.05, for all). When compared to the baseline control period, fetal ΔcTnT was significantly modified throughout UCO series: 5.0% (-3; 45) in phase A, 51% (4; 263) in phase B, and 77% (56.5; 269) in phase C (p < 0.05 for all).

CONCLUSIONS

S100B and c-TnT increased when fetal acidosis occurred, which reflects the potential neurological damage and fetal cardiovascular adaptation.

Measuring the impact of cardiotocograph decision support software on neonatal outcomes: A propensity score-matched observational study

BACKGROUND

This study follows the 2017 UK INFANT Collaborative Group RCT, which compared neonatal outcomes with and without the use of the INFANT cardiotocograph decision support system for over 46 000 patients in labour. The original trial failed to demonstrate a significant improvement to neonatal outcomes; however, the study design was subject to methodological critique.

AIMS

This Australian retrospective cohort study aimed to report perinatal outcomes before and after the introduction of INFANT decision support software for cardiotocograph use in labour.

MATERIALS AND METHODS

The study cohort was divided into two equivalent 18-month epochs, before and after the introduction of INFANT-Guardian® CTG decision support system. Propensity score matching analysis was undertaken to balance pre- and post-implementation groups by baseline covariates. The matched cohort included 11 154 public-funded women between November 2016 and 2019, with a singleton live fetus ≥34 + 0 weeks, being induced or in spontaneous labour. The main outcome measures were: a composite measure of serious adverse neonatal outcome comprising of one or more of: admission to intensive care nursery >48 h, Apgar <4 at 5 min, cord arterial pH <7.0, hypoxic ischaemic encephalopathy grade 2 or 3, therapeutic hypothermia, neonatal death.

RESULTS

The incidence of the composite primary outcome was significantly lower following implementation of INFANT (0.57% vs. 1.00%; OR 0.57, 95%CI 0.37-0.88; P = 0.01). A significant reduction in nursery admission >48 h was also observed (0.05% vs. 0.30%; OR 0.18, 95%CI 0.05-0.60; P = 0.002).

CONCLUSIONS

INFANT software is associated with a reduction in serious adverse neonatal outcomes, without increasing the rate of operative delivery.

Is Glycated Hemoglobin A1c Level Associated with Adverse Pregnancy Outcomes of Women Affected by Pre-Gestational Diabetes?

Background and Objectives: This observational study aims to determine the correlation between glycemic control with the HbA1c value and adverse obstetric outcome in women affected by pre-gestational diabetes. Materials and Methods: A retrospective analysis has been performed at the University Hospital of Udine. Only patients with a singleton pregnancy, pre-gestational diabetes, and known level of Hb A1c throughout pregnancy were included in the study. Results: According to the HbA1c level, at the beginning of pregnancy, 49 patients with HbA1c ≤ 7.0% were compared with 45 patients with HbA1c > 7.0%. Maternal age at diagnosis of the disease was significantly higher in the group with HbA1c ≤ 7% than in the group with HbA1c > 7%, 26.00 (18.00–32.00) vs. 20.00 (12.50–27.00). Women with HbA1c ≤ 7.0% reached, at term of pregnancy, significantly lower levels of HbA1c, 5.8% (5.7–6.0) vs. 6.7% (6.3–7.3). Daily insulin units were statistically different between the two groups at the end of pregnancy (47.92 (39.00–67.30) vs. 64.00 (48.00–82.00)). Proteinuria was significantly higher in the group with HbA1c > 7.0%, who delivered at earlier gestational age (37.57 (35.57–38.00) vs. 38.14 (38.00–38.43). Moreover, women with HbA1c > 7.0% had a significantly higher prevalence of an adverse composite outcome. Of note, in multivariate logistic regression analysis, pregnancy complications were significantly correlated to pre-pregnancy HbA1c > 7.0% (OR 2.95 CI.95 1.16–7.48, p < 0.05) independently of age, insulin treatment, and type of diabetes. Conclusions: Our data, obtained from a single-center cohort study, suggest that starting pregnancy with poor glycemic control might predict more complex management of diabetes in the following trimesters.

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.

Trends and predictors of in-hospital mortality among babies with hypoxic ischaemic encephalopathy at a tertiary hospital in Nigeria: A retrospective cohort study

Background

Globally, approximately 9 million neonates develop perinatal asphyxia annually of which about 1.2 million die. Majority of the morbidity and mortality occur in Low and middle-income countries. However, little is known about the current trend in incidence, and the factors affecting mortality from hypoxic ischaemic encephalopathy (HIE), in Nigeria.

Objective

We assessed the trends in incidence and fatality rates and evaluated the predictors of mortality among babies admitted with HIE over five years at the Lagos University Teaching Hospital.

Methods

A temporal trend analysis and retrospective cohort study of HIE affected babies admitted to the neonatal unit of a Nigerian Teaching Hospital was conducted. The socio-demographic and clinical characteristics of the babies and their mothers were extracted from the neonatal unit records. Kaplan-Meir plots and Multivariable Cox proportional hazard ratio was used to evaluate the survival experienced using Stata version 16 (StataCorp USA) statistical software.

Results

The median age of the newborns at admission was 26.5 (10–53.5) hours and the male to female ratio was 2.1:1. About one-fifth (20.8%) and nearly half (47.8%) were admitted within 6 hours and 24 hours of life respectively, while majority (84%) of the infants were out-born. The prevalence and fatality rate of HIE in our study was 7.1% and 25.3% respectively. The annual incidence of HIE among the hospital admissions declined by 1.4% per annum while the annual fatality rate increased by 10.3% per annum from 2015 to 2019. About 15.7% died within 24 hours of admission. The hazard of death was related to the severity of HIE (p = 0.001), antenatal booking status of the mother (p = 0.01) and place of delivery (p = 0.03).

Conclusion

The case fatality rate of HIE is high and increasing at our centre and mainly driven by the pattern of admission of HIE cases among outborn babies. Thus, community level interventions including skilled birth attendants at delivery, newborn resuscitation trainings for healthcare personnel and capacity building for specialized care should be intensified to reduce the burden of HIE.

Enigma of maternity service safety improvements and increasing expression of patient dissatisfaction

There have been gradual and continual improvements in maternity care in the UK. This has been paradoxically accompanied by increasing censure by authorities for adverse outcomes and public expression of dissatisfaction. Serious maternal and perinatal adverse outcomes have a devastating effect. Grieving families need an honest explanation, continued support and reassurance that lessons are being sought and learnt. Additionally, the public would welcome the acknowledgement of limitations of healthcare and the science itself; and that the adverse outcomes can be minimised but not eradicated. Blame culture is harmful to the clinicians, healthcare system and, ultimately, patients. The controversial issue of intrapartum fetal monitoring best illustrates the urgent need to reform mistaken science in addition to organisational and cultural improvements. Most enquiries do not critique bad science or guidelines but only birth attendants. The healthcare outcomes must continue to improve through investigations, reviews, openness, medical progress and by helping the clinicians to mitigate the limitations of scientific knowledge, resources and human factors.

A physiologically validated rat model of term birth asphyxia with seizure generation after, not during, brain hypoxia

OBJECTIVE

Birth asphyxia (BA) is often associated with seizures that may exacerbate the ensuing hypoxic-ischemic encephalopathy. In rodent models of BA, exposure to hypoxia is used to evoke seizures, that commence already during the insult. This is in stark contrast to clinical BA, in which seizures are typically seen upon recovery. Here, we introduce a term-equivalent rat model of BA, in which seizures are triggered after exposure to asphyxia.

METHODS

Postnatal day 11-12 male rat pups were exposed to steady asphyxia (15 min; air containing 5% O2  + 20% CO2 ) or to intermittent asphyxia (30 min; three 5 + 5-min cycles of 9% and 5% O2 at 20% CO2 ). Cortical activity and electrographic seizures were recorded in freely behaving animals. Simultaneous electrode measurements of intracortical pH, Po2 , and local field potentials (LFPs) were made under urethane anesthesia.

RESULTS

Both protocols decreased blood pH to <7.0 and brain pH from 7.3 to 6.7 and led to a fall in base excess by 20 mmol·L-1 . Electrographic seizures with convulsions spanning the entire Racine scale were triggered after intermittent but not steady asphyxia. In the presence of 20% CO2 , brain Po2 was only transiently affected by 9% ambient O2 but fell below detection level during the steps to 5% O2 , and LFP activity was nearly abolished. Post-asphyxia seizures were strongly suppressed when brain pH recovery was slowed down by 5% CO2 .

SIGNIFICANCE

The rate of brain pH recovery has a strong influence on post-asphyxia seizure propensity. The recurring hypoxic episodes during intermittent asphyxia promote neuronal excitability, which leads to seizures only after the suppressing effect of the hypercapnic acidosis is relieved. The present rodent model of BA is to our best knowledge the first one in which, consistent with clinical BA, behavioral and electrographic seizures are triggered after and not during the BA-mimicking insult.

Lack of evidence for impaired preload or Bezold-Jarisch activation during brief umbilical cord occlusions in fetal sheep

Impaired cardiac preload secondary to umbilical cord occlusion (UCO) has been hypothesized to contribute to intrapartum decelerations, brief falls in fetal heart rate (FHR), through activation of the Bezold-Jarisch reflex. This cardioprotective reflex increases parasympathetic and inhibits sympathetic outflows triggering hypotension, bradycardia, and peripheral vasodilation, but its potential to contribute to intrapartum decelerations has never been systematically examined. In this study, we performed bilateral cervical vagotomy to remove the afferent arm and the efferent parasympathetic arm of the Bezold-Jarisch reflex. Twenty-two chronically instrumented fetal sheep at 0.85 of gestation received vagotomy (n = 7) or sham vagotomy (control, n = 15), followed by three 1-min complete UCOs separated by 4-min reperfusion periods. UCOs in control fetuses were associated with a rapid fall in FHR and reduced femoral blood flow mediated by intense femoral vasoconstriction, leading to hypertension. Vagotomy abolished the rapid fall in FHR (P < 0.001) and, despite reduced diastolic filling time, increased both carotid (P < 0.001) and femoral (P < 0.05) blood flow during UCOs, secondary to carotid vasodilation (P < 0.01) and delayed femoral vasoconstriction (P < 0.05). Finally, vagotomy was associated with an attenuated rise in cortical impedance during UCOs (P < 0.05), consistent with improved cerebral substrate supply. In conclusion, increased carotid and femoral blood flows after vagotomy are consistent with increased left and right ventricular output, which is incompatible with the hypothesis that labor-like UCOs impair ventricular filling. Overall, the cardiovascular responses to vagotomy do not support the hypothesis that the Bezold-Jarisch reflex is activated by UCO. The Bezold-Jarisch reflex is therefore mechanistically unable to contribute to intrapartum decelerations.

Deceleration area and capacity during labour-like umbilical cord occlusions identify evolving hypotension: a controlled study in fetal sheep

OBJECTIVE

Cardiotocography is widely used to assess fetal well-being during labour. The positive predictive value of current clinical algorithms to identify hypoxia-ischaemia is poor. In experimental studies, fetal hypotension is the strongest predictor of hypoxic-ischaemic injury. Cohort studies suggest that deceleration area and deceleration capacity of the fetal heart rate trace correlate with fetal acidaemia, but it is not known whether they are indices of fetal arterial hypotension.

DESIGN

Prospective, controlled study.

SETTING

Laboratory.

SAMPLE

Near-term fetal sheep.

METHODS

One minute of complete umbilical cord occlusions (UCOs) every 5 minutes (1:5 min, n = 6) or every 2.5 minutes (1:2.5 min, n = 12) for 4 hours or until fetal mean arterial blood pressure fell <20 mmHg.

MAIN OUTCOME MEASURES

Deceleration area and capacity during the UCO series were related to evolving hypotension.

RESULTS

The 1:5 min group developed only mild metabolic acidaemia, without hypotension. By contrast, 10/12 fetuses in the 1:2.5-min group progressively developed severe metabolic acidaemia and hypotension, reaching 16.8 ± 0.9 mmHg after 71.2 ± 6.7 UCOs. Deceleration area and capacity remained unchanged throughout the UCO series in the 1:5-min group, but progressively increased in the 1:2.5-min group. The severity of hypotension was closely correlated with both deceleration area (P < 0.001, R²  = 0.66, n = 18) and capacity (P < 0.001, R²  = 0.67, n = 18). Deceleration area and capacity predicted development of hypotension at a median of 103 and 123 minutes before the final occlusion, respectively.

CONCLUSIONS

Both deceleration area and capacity were strongly associated with developing fetal hypotension, supporting their potential to improve identification of fetuses at risk of hypotension leading to hypoxic-ischaemic injury during labour.

TWEETABLE ABSTRACT

Deceleration area and capacity of fetal heart rate identify developing hypotension during labour-like hypoxia.

"The First Thousand Days" Define a Fetal/Neonatal Neurology Program

Gene-environment interactions begin at conception to influence maternal/placental/fetal triads, neonates, and children with short- and long-term effects on brain development. Life-long developmental neuroplasticity more likely results during critical/sensitive periods of brain maturation over these first 1,000 days. A fetal/neonatal program (FNNP) applying this perspective better identifies trimester-specific mechanisms affecting the maternal/placental/fetal (MPF) triad, expressed as brain malformations and destructive lesions. Maladaptive MPF triad interactions impair progenitor neuronal/glial populations within transient embryonic/fetal brain structures by processes such as maternal immune activation. Destructive fetal brain lesions later in pregnancy result from ischemic placental syndromes associated with the great obstetrical syndromes. Trimester-specific MPF triad diseases may negatively impact labor and delivery outcomes. Neonatal neurocritical care addresses the symptomatic minority who express the great neonatal neurological syndromes: encephalopathy, seizures, stroke, and encephalopathy of prematurity. The asymptomatic majority present with neurologic disorders before 2 years of age without prior detection. The developmental principle of ontogenetic adaptation helps guide the diagnostic process during the first 1,000 days to identify more phenotypes using systems-biology analyses. This strategy will foster innovative interdisciplinary diagnostic/therapeutic pathways, educational curricula, and research agenda among multiple FNNP. Effective early-life diagnostic/therapeutic programs will help reduce neurologic disease burden across the lifespan and successive generations.

Effects of antenatal dexamethasone and hyperglycemia on cardiovascular adaptation to asphyxia in preterm fetal sheep

Antenatal glucocorticoids improve outcomes among premature infants but are associated with hyperglycemia, which can exacerbate hypoxic-ischemic injury. It is still unclear how antenatal glucocorticoids or hyperglycemia modulate fetal cardiovascular adaptations to severe asphyxia. In this study, preterm fetal sheep received either saline or 12 mg im maternal dexamethasone, followed 4 h later by complete umbilical cord occlusion (UCO) for 25 min. An additional cohort of fetuses received titrated glucose infusions followed 4 h later by UCO to control for the possibility that hyperglycemia contributed to the cardiovascular effects of dexamethasone. Fetuses were studied for 7 days after UCO. Maternal dexamethasone was associated with fetal hyperglycemia (P < 0.001), increased arterial pressure (P < 0.001), and reduced femoral (P < 0.005) and carotid (P < 0.05) vascular conductance before UCO. UCO was associated with bradycardia, femoral vasoconstriction, and transient hypertension. For the first 5 min of UCO, fetal blood pressure in the dexamethasone-asphyxia group was greater than saline-asphyxia (P < 0.001). However, the relative increase in arterial pressure was not different from saline-asphyxia. Fetal heart rate and femoral vascular conductance fell to similar nadirs in both saline and dexamethasone-asphyxia groups. Dexamethasone did not affect the progressive decline in femoral vascular tone or arterial pressure during continuing UCO. By contrast, there were no effects of glucose infusions on the response to UCO. In summary, maternal dexamethasone but not fetal hyperglycemia increased fetal arterial pressure before and for the first 5 min of prolonged UCO but did not augment the cardiovascular adaptations to acute asphyxia.