Fetal hypoxic and ischemic injuries

The contribution of low Apgar scores in identifying neonates with short-term morbidities in a large single center cohort

OBJECTIVE

To evaluate the association and utility of low 1- and 5-min Apgar scores to identify short-term morbidities in a large newborn cohort.

METHODS

15,542 infants >22 weeks gestation from a single center were included. Clinical data and low Apgar scores were analyzed for significance to ten short-term outcomes and were used to construct Receiver Operating Characteristic Curves and the AUC calculated for ten outcomes.

RESULTS

A low Apgar score related to all (1-min) or most (5-min) outcomes by univariate and multivariate logistic regression analysis. Including any of the 4 low Apgar scores only improved the clinical factor AUC by 0.9% ± 2.7% (±SD) and was significant in just 5 of the 40 score/outcome scenarios.

CONCLUSION

The contribution of a low Apgar score for identifying risk of short-term morbidity does not appear to be clinically significant.

Approaches to Preventing Intrapartum Fetal Injury

Electronic fetal monitoring (EFM) was introduced into obstetric practice in 1970 as a test to identify early deterioration of fetal acid-base balance in the expectation that prompt intervention ("rescue") would reduce neonatal morbidity and mortality. Clinical trials using a variety of visual or computer-based classifications and algorithms for intervention have failed repeatedly to demonstrate improved immediate or long-term outcomes with this technique, which has, however, contributed to an increased rate of operative deliveries (deemed "unnecessary"). In this review, we discuss the limitations of current classifications of FHR patterns and management guidelines based on them. We argue that these clinical and computer-based formulations pay too much attention to the detection of systemic fetal acidosis/hypoxia and too little attention not only to the pathophysiology of FHR patterns but to the provenance of fetal neurological injury and to the relationship of intrapartum injury to the condition of the newborn. Although they do not reliably predict fetal acidosis, FHR patterns, properly interpreted in the context of the clinical circumstances, do reliably identify fetal neurological integrity (behavior) and are a biomarker of fetal neurological injury (separate from asphyxia). They provide insight into the mechanisms and trajectory (evolution) of any hypoxic or ischemic threat to the fetus and have particular promise in signaling preventive measures (1) to enhance the outcome, (2) to reduce the frequency of "abnormal" FHR patterns that require urgent intervention, and (3) to inform the decision to provide neuroprotection to the newborn.

Effects of acute tocolysis using ritodrine hydrochloride on foetal heart rate patterns in intrauterine foetal resuscitation: a retrospective, single-centre observational study

No consistent recommendations concerning the preferred tocolytic agents for intrauterine foetal resuscitation are available. We evaluated the effects of acute tocolysis (AT) using ritodrine hydrochloride on foetal heart rate (FHR) patterns and neonatal outcomes. We retrospectively analysed the data of patients undergoing emergency caesarean section because of non-reassuring foetal status indicated by foetal scalp electrodes. Patients were classified into AT (ritodrine hydrochloride approximately 500 µg/min) and control groups with 15 and 12 participants, respectively. FHR patterns, Apgar scores, umbilical arterial analysis, and neonatal admission were compared. All participants had FHR category II; decelerations disappeared in all foetuses in the AT group, with no significant difference in neonatal outcomes. The AT group had a higher baseline FHR and lower short-term FHR variability than the control group, indicating foetal autonomic responses. Further studies are needed to clarify the effects of AT on FHR patterns, neonatal outcomes, and foetal and neonatal autonomic responses.Impact statementWhat is already known on this subject? The usefulness of acute tocolysis using ritodrine hydrochloride has been well-documented in several studies; however, such an application often induces side effects, such as maternal tachycardia, palpitations, and tremors.What the results of this study add? The short-term administration of ritodrine hydrochloride eliminated decelerations, with no significant difference in neonatal outcomes in pregnant women with foetal heart rate category II. Meanwhile, there were higher foetal heart rate and lower short-term foetal heart rate variability in pregnant women administered with ritodrine hydrochloride, indicating foetal autonomic responses.What the implications are of these findings for clinical practice and/or further research? Ritodrine hydrochloride administration, even for short-term, appears to be associated with foetal autonomic responses. Further studies with stratification of patient groups based on the severity and aetiology of non-reassuring foetal status, including pregnant women with foetal category III, would elucidate the risk and benefit of acute tocolysis using ritodrine hydrochloride, based on foetal heart rate patterns, neonatal outcomes, and foetal and neonatal autonomic responses.

Maternal pre-pregnancy body mass index and foetal acidosis in vaginal and caesarean deliveries: The Japan Environment and Children's Study

A high maternal body mass index (BMI) is associated with increased risks of asphyxia-related neonatal morbidity. We evaluated the association between maternal pre-pregnancy BMI and foetal acidosis while accounting for the mode of delivery. Participants from the Japan Environment and Children's Study with singleton pregnancies after 22 weeks of gestation who gave birth during 2011-2014 were included. The participants (n = 71,799) were categorised into five groups according to the pre-pregnancy BMI: G1 (BMI < 18.5 kg/m²), G2 (18.5 to < 20.0 kg/m²), G3 (20.0 to < 23.0 kg/m²), G4 (23.0 to < 25.0 kg/m²), and G5 (≥ 25.0 kg/m²). Foetal acidosis was defined as umbilical artery pH (UmA-pH) < 7.20 or < 7.10. Multiple logistic regression analyses were used to evaluate the effect of pre-pregnancy BMI on foetal acidosis risk, accounting for the mode of delivery. In Japanese women, pre-pregnancy BMI ≥ 25.0 kg/m² significantly increased the likelihood of foetal acidosis in newborns delivered vaginally. We found no association between pre-pregnancy BMI and foetal acidosis in newborns delivered via caesarean section. Counselling for body weight control before pregnancy and adequate management and selection of the mode of delivery in pregnant women with a high BMI who are in labour may be essential to avoid foetal acidosis.

Detection of Preventable Fetal Distress During Labor From Scanned Cardiotocogram Tracings Using Deep Learning

Despite broad application during labor and delivery, there remains considerable debate about the value of electronic fetal monitoring (EFM). EFM includes the surveillance of fetal heart rate (FHR) patterns in conjunction with the mother's uterine contractions, providing a wealth of data about fetal behavior and the threat of diminished oxygenation and cerebral perfusion. Adverse outcomes universally associate a fetal injury with the failure to timely respond to FHR pattern information. Historically, the EFM data, stored digitally, are available only as rasterized pdf images for contemporary or historical discussion and examination. In reality, however, they are rarely reviewed systematically or purposefully. Using a unique archive of EFM collected over 50 years of practice in conjunction with adverse outcomes, we present a deep learning framework for training and detection of incipient or past fetal injury. We report 94% accuracy in identifying early, preventable fetal injury intrapartum. This framework is suited for automating an early warning and decision support system for maintaining fetal well-being during the stresses of labor. Ultimately, such a system could enable obstetrical care providers to timely respond during labor and prevent both urgent intervention and adverse outcomes. When adverse outcomes cannot be avoided, they can provide guidance to the early neuroprotective treatment of the newborn.

Umbilical cord lactate compared with pH as predictors of intrapartum asphyxia

Despite advances in fetal monitoring during labor, one of the most critical causes of neonatal death and neurologic injuries remains intrapartum asphyxia. Umbilical cord gases can be used to detect acidosis and fetal distress. We conducted a retrospective, multicenter study to evaluate umbilical cord blood pH and lactate as a mean of evaluating the degree of intrapartum hypoxia and also to establish which of the two is more reliable in predicting morbidity in term neonates. The present study utilized a total of 124 cases that met the criteria for intrapartum asphyxia and 150 normal term newborns that were randomly selected as case control. Both umbilical cord lactate and pH proved to be accurate predictors of neonatal morbidity caused by intrapartum hypoxia. Lactate proved to be superior to pH in predicting adverse neonatal outcome. The greatest sensibility and specificity in predicting intrapartum asphyxia were achieved in our study by using a cutoff value of 3.75 mmol/l for lactate and 7.24 for pH.

Gestational weight gain and foetal acidosis in vaginal and caesarean deliveries: The Japan Environment and Children's Study

Inappropriate gestational weight gain (GWG), either above or below the recommended values, has been associated with an increased risk of adverse obstetric outcomes. To evaluate the risks of GWG for foetal acidosis according to pre-pregnancy body mass index (BMI) and mode of delivery, we analysed women with singleton pregnancies between 2011 and 2014 in the Japan Environment and Children’s Study. Participants (n = 71,799) were categorised according to pre-pregnancy BMI. GWG was categorised into insufficient, appropriate, or excessive. Foetal acidosis was defined as umbilical artery pH (UmA-pH) < 7.20 or < 7.10. Multiple logistic regressions were performed for each BMI category to identify the risks of GWG for foetal acidosis, accounting for the mode of delivery. Excessive GWG was significantly associated with increased foetal acidosis in overweight women and in women whose pre-pregnancy BMI was 23.0–25.0 kg/m² especially in those with vaginal deliveries. Conversely, excessive GWG was not significantly associated with increased foetal acidosis in obese women and in women whose pre-pregnancy BMI was  ≥ 25.0 kg/m².

Umbilical cord arterial and venous gases, ionogram, and glucose level for predicting neonatal morbidity at term

OBJECTIVE

To determine which parameter of umbilical arterial cord gas analysis, pH, base deficit, lactate concentration, ionogram values, or glucose level index is the best predictor of neonatal morbidity at term.

DESIGN

We conducted a 15-month retrospective cohort study that included all nonanomalous, singleton, term births at a single center. The predictive ability of lactate concentration, base deficit, pH, ionogram values, and glucose level were compared using receiver-operating characteristic curves for global and neurological composite morbidity. Optimal cutoff values for lactate concentration, base deficit, and pH were estimated based on their maximum area under the curve.

RESULTS

We included 5161 newborns: 52 (1.01 %) had global composite morbidity, and 17 had (0.33 %) neurological composite morbidity. Blood levels of potassium, calcium, natremia, glucose level, and HCO₃^- did not differ significantly between groups. pH, partial pressure of CO₂, partial pressure of O₂, base deficit, and lactate levels differed significantly between neonates in the groups with and without global composite morbidity. Nearly similar results were found for neurological composite morbidity. The predictive ability did not differ between arterial pH and arterial lactate concentration (P = .25) and base deficit (P = .79). Optimal cutoff values to predict global composite morbidity were arterial pH 7.144, venous pH 7.236, and arterial lactate concentration 6.5 mmol/L.

CONCLUSIONS

Acid-base status analysis remains the best objective indicator for predicting neonatal morbidity and can be estimated using pH, lactate, or base deficit. Ionogram cord blood composition and glucose level do not appear to be useful for this purpose.

Combined prenatal and postnatal prediction of early neonatal compromise risk

OBJECTIVE

Electronic fetal monitoring/cardiotocography (EFM) is nearly ubiquitous, but almost everyone acknowledges there is room for improvement. We have contextualized monitoring by breaking it down into quantifiable components and adding to that, other factors that have not been formally used: i.e. the assessment of uterine contractions, and the presence of maternal, fetal, and obstetrical risk factors. We have created an algorithm, the Fetal Reserve Index (FRI) that significantly improves the detection of at-risk cases. We hypothesized that extending our approach of monitoring to include the immediate newborn period could help us better understand the physiology and pathophysiology of the decrease in fetal reserve during labor and the transition from fetal to neonatal homeostasis, thereby further honing the prediction of outcomes. Such improved and earlier understanding could then potentiate earlier, and more targeted use of neuroprotective attempts during labor treating decreased fetal reserve and improving the fetus' transition from fetal to neonatal life minimizing risk of neurologic injury.

STUDY DESIGN

We have analyzed a 45-year-old research database of closely monitored labors, deliveries, and an additional hour of continuous neonatal surveillance. We applied the FRI prenatally and created a new metric, the INCHON index that combines the last FRI with umbilical cord blood and 4-minute umbilical artery blood parameters to predict later neonatal acid/base balance. Using the last FRI scores, we created 3 neonatal groups. Umbilical cord and catheterized umbilical artery bloods at 4, 8, 16, 32, and 64 minutes were measured for base excess, pH, and PO₂. Continuous neonatal heart rate was scored for rate, variability, and reactivity.

RESULTS

Neonates commonly do not make a smooth transition from fetal to postnatal physiology. Even in low risk babies, 85% exhibited worsening pH and base excess during the first 4 minutes; 34% of neonates reached levels considered at high risk for metabolic acidosis (≤-12 mmol/L) and neurologic injury. Neonatal heart rate commonly exhibited sustained, significant tachycardia with loss of reactivity and variability. One quarter of all cases would be considered Category III if part of the fetal tracing. Our developed metrics (FRI and INCHON) clearly discriminated and predicted low, medium, and high-risk neonatal physiology.

CONCLUSIONS

The immediate neonatal period often imposes generally unrecognized risks for the newborn. INCHON improves identification of decreased fetal reserve and babies at risk, thereby permitting earlier intervention during labor (intrauterine resuscitation) or potentially postnatally (brain cooling) to prevent neurologic injury. We believe that perinatal management would be improved by routine, continuous neonatal monitoring - at least until heart rate reactivity is restored. FRI and INCHON can help identify problems much earlier and more accurately than currently and keep fetuses and babies in better metabolic shape.

The Fetal Reserve Index Significantly Outperforms ACOG Category System in Predicting Cord Blood Base Excess and pH: A Methodological Failure of the Category System

OBJECTIVE

Electronic fetal monitoring (EFM) has been used extensively for almost 50 years but performs poorly in predicting and preventing adverse neonatal outcome. In recent years, the current "enhanced" classification of patterns (category I-III system [CAT]) were introduced into routine practice without corroborative studies, which has resulted in even EFM experts lamenting its value. Since abnormalities of arterial cord blood parameters correlate reasonably well with risk of fetal injury, here we compare the statistical performance of EFM using the current CAT system with the Fetal Reserve Index (FRI) for predicting derangements in base excess (BE), pH, and pO₂ in arterial cord blood.

METHODS

We utilized a research database of labor data, including umbilical cord blood measurements to assess patients by both worst CAT and last FRI classifications. We compared these approaches for their ability to predict BE, pH, and pO₂ in cord blood.

RESULTS

The FRI showed a clear correlation with cord blood BE and pH with BE being more highly correlated than pH. The CAT was much less predictive than FRI (P < .05). The CAT II cases had FRI scores across the spectrum of severity of FRI designations and as such provide little clinical discrimination. The PO₂ was not discriminatory, in part, because of neonatal interventions.

CONCLUSIONS

The Fetal Reserve Index (FRI) provides superior performance over CAT classification of FHR patterns in predicting the BE and pH in umbilical cord blood. Furthermore, the CAT system fails to satisfy multiple fundamental principles required for successful screening programs. Limitations of CAT are further compounded by assumptions about physiology that are not consistent with clinical observations.

Safely lowering the emergency Cesarean and operative vaginal delivery rates using the Fetal Reserve Index

Objective: The cardiotocograph (CTG) or electronic fetal monitoring (EFM) was developed to prevent fetal asphyxia and subsequent neurological injury. From a public health perspective, it has failed these objectives while increasing emergency operative deliveries (emergency operative deliveries (EODs) - emergency cesarean delivery or operative vaginal delivery) for newborns, who in retrospect, actually did not require the assistance. EODs increase the risks of complications and stress for patients, families, and medical personnel. A safe reduction in the need for EOD will likely reduce both the overall Cesarean section rate as well as the risk of fetal neurological injury during labor to which it is related. We have developed the fetal reserve index (FRI), which is more comprehensive than CTG as a new screening method for early identification of the fetus at-risk of both neurological harm and the need to "rescue" by means of an EOD. Here, we compare prospectively the need for EOD in two groups of parturients undergoing a trial of labor at term. One group was managed conventionally, the other by the principles of the FRI.Study design: We compared the need for EOD of 800 parturients with singleton cases undergoing a trial of labor at term entering with normal CTG patterns (ACOG category 1). Patients were either treated routinely (400 - "early cases") or in a second group seen later actively managed using the principles of the FRI (400 - "late cases"). The FRI includes measurements of five components of the CTG: rate, variability, decelerations, accelerations, and abnormal uterine activity combined with the presence of medical, obstetrical, and fetal risk factors. The 8-point metric categorizes cases as "green", "yellow", and "red" with the latter being at risk.Results: All 800 patients delivered babies, who were discharged in the usual time course with no untoward outcomes noted. The incidence of red zone scores was comparable in the two groups (≈25%), but the use of intrauterine resuscitation (IR) when reaching the red zone in the late group (47%) was more than double the incidence in the early group (20%) (p < .001). Despite (or because of) this, EODs were significantly reduced in the late group, from 17.3 to 4.0% (p < .001). Further, the late group spent less time in the red zone without increasing overall time in labor. Overall, EOD cases averaged >1 h in the red zone versus 0.5 h for non-EODs.Conclusions: The FRI may provide a metric to reduce EODs and by extension also reduce the risks of both cesarean delivery and adverse fetal/neonatal outcomes. The safe avoidance of EOD would seem to be an important metric to assess the quality of intrapartum management. This study represents the first attempt to apply the principles of the FRI "live" for the concurrent management of patients during labor. These promising results, if confirmed, in larger sample sizes, set the stage for our computerization of the FRI for widespread study. Benefits appear to come from identification and early, conservative management of fetal deterioration before the need to "rescue" the fetus by EOD.

Neonatal subcortical bruising

A specific type of acute brain injury can occur during birth, presenting on ultrasound examination with focal, unilateral, or asymmetrical change in the core of the superior frontal gyri. Ultrasound inspection of the superior gyri near the convexity of the frontal lobe is warranted following mechanically difficult delivery.

Umbilical lactate as a measure of acidosis and predictor of neonatal risk: a systematic review

BACKGROUND

Umbilical cord lactate is one approach to measuring acidosis and intrapartum hypoxia, knowledge of which may be helpful for clinicians involved in the care of women and newborns.

OBJECTIVE

To synthesise the evidence on accuracy of umbilical cord lactate in measuring acidosis and predicting poor neonatal outcome.

SEARCH STRATEGY

Studies published and unpublished between 1990 and 2014 from PubMed/Medline, EMBASE, Cochrane Central Register of Controlled Trials, and clinicaltrials.gov were assessed.

SELECTION CRITERIA

Cross-sectional and randomised studies that assessed fetal acidosis (using lactate as the index test) with or without an assessment of neonatal outcome.

DATA COLLECTION AND ANALYSIS

Correlations between index and reference test(s) were recorded, as were the raw data to classify the predictive ability of umbilical lactate for neonatal outcomes. Meta-analysis of correlation was performed. We plotted estimates of the studies' observed sensitivities and specificities on Forest plots with 95% confidence intervals (CI). Where possible, we combined data using meta-analysis, applying the hierarchical summary receiver operating characteristics model and a bivariate model.

MAIN RESULTS

Twelve studies were included. Umbilical lactate correlated with pH [pooled effect size (ES) -0.650; 95% CI -0.663 to -0.637, P < 0.001], base excess (ES -0.710; 95% CI -0.721 to -0.699, P < 0.001), and Apgar scores at 5 minutes (ES 0.300; 95% 0.193-0.407, P < 0.001). Umbilical lactate had pooled sensitivity and specificity for predicting neonatal neurological outcome including hypoxic ischaemic encephalopathy of 69.7% (95% CI 23.8-94.4%) and 93% (95% CI 86.8-96.3%).

AUTHORS' CONCLUSION

Umbilical cord lactate is a clinically applicable, inexpensive and effective way to measure acidosis and is a tool that may be used in the assessment of neonatal outcome.

TWEETABLE ABSTRACT

Umbilical cord lactate: a clinically applicable, inexpensive, effective way to measure intrapartum acidosis.

Acute Blockage of Notch Signaling by DAPT Induces Neuroprotection and Neurogenesis in the Neonatal Rat Brain After Stroke

Notch signaling is critically involved in various biological events. Notch undergoes cleavage by the γ-secretase enzyme to release Notch intracellular domain that will translocate into nucleus to result in expression of target gene. γ-Secretase inhibitors have been developed as potential treatments for neurological degenerative diseases, but its effects against ischemic injury remain relatively uncertain. In the present study, we demonstrated that N-[N-(3, 5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT), a γ-secretase inhibitor not only rescued the cerebral hypoperfusion or ischemia neonatal rats from death, reduced apoptosis in penumbra, but also reduced brain infarct size. Furthermore, DAPT elicited some morphologic hallmarks such as neurogenesis and angiogenesis that related to the brain repair and functional recovery after stroke: increased accumulations of newborn cells in the peri-infarct region with a higher fraction of them adopting immature neuronal and glial markers instead of microglial markers on 5 days, enhanced vascular densities in penumbra at 14 days, and evident regulations of the gene profiles associated with neurogenesis in penumbral tissues. The current results suggest that DAPT is a potential neuroprotectants against ischemic injury in immature brain, and future treatment strategies such as clinical trials using γ-secretase inhibitors would be an attractive therapy for perinatal ischemia.

Litigation related to intrapartum fetal surveillance

The role of intrapartum care including cardiotocography (CTG) monitoring in cases of perinatal neurological injury receives considerable debate in both clinical and medicolegal settings. The debate, however, has distracted attention from fundamental questions about the timing, mechanism, and preventability of perinatal injury. CTG tracings are used as a surrogate for asphyxia with the timing of intervention ("rescue") predicated on the presumed severity of asphyxia. Using CTG in this way has prevented intrapartum stillbirth, but it has not reduced the long-term injury in part, because, contrary to popular belief, the majority of intrapartum fetal injuries are unassociated with severe hypoxia or severe neonatal depression. This article describes the timing and mechanisms, including mechanical factors, of intrapartum perinatal injury and the benefit of using the CTG, not for the purpose of "rescue", but for identifying risk factors for fetal injury and keeping the fetus out of harm's way.

Maternity care and liability: most promising policy strategies for improvement

BACKGROUND

The present liability system is not serving well childbearing women and newborns, maternity care clinicians, or maternity care payers. Examination of evidence about the impact of this system on maternity care led us to identify seven aims for a high-functioning liability system in this clinical context. Herein, we identify policy strategies that are most likely to meet these aims and contribute to needed improvements. A companion paper considers strategies that hold little promise.

METHODS

We considered whether 25 strategies that have been used or proposed for improvement have met or could meet the seven aims. We used a best available evidence approach and drew on more recent empirical legal studies and health services research about maternity care and liability when available, and considered other studies when unavailable.

FINDINGS

Ten strategies seem to have potential to improve liability matters in maternity care across multiple aims. The most promising strategy--implementing rigorous maternity care quality improvement (QI) programs--has led to better quality and outcomes of care, and impressive declines in liability claims, payouts, and premium levels.

CONCLUSIONS

A number of promising strategies warrant demonstration and evaluation at the level of states, health systems, or other appropriate entities. Rigorous QI programs have a growing track record of contributing to diverse aims of a high-functioning liability system and seem to be a win-win-win prevention strategy for childbearing families, maternity care providers, and payers. Effective strategies are also needed to assist families when women and newborns are injured.

Why the term neonatal encephalopathy should be preferred over neonatal hypoxic-ischemic encephalopathy

The unresponsiveness of the full-term newborn is sometimes attributed to asphyxia, even when no severe physiologic disturbance occurred during labor and delivery. The controversy about whether to use the name "hypoxic-ischemic encephalopathy" or "newborn encephalopathy" has recently flared in publications directed toward pediatricians and neurologists. In this clinic opinion piece, I discuss the importance to obstetricians of this decision and explain why "newborn encephalopathy" should be the default term.

Neonatal encephalopathy: an inadequate term for hypoxic-ischemic encephalopathy

This Point of View article addresses neonatal encephalopathy (NE) presumably caused by hypoxia-ischemia and the terminology currently in wide use for this disorder. The nonspecific term NE is commonly utilized for those infants with the clinical and imaging characteristics of neonatal hypoxic-ischemic encephalopathy (HIE). Multiple magnetic resonance imaging studies of term infants with the clinical setting of presumed hypoxia-ischemia near the time of delivery have delineated a topography of lesions highly correlated with that defined by human neuropathology and by animal models, including primate models, of hypoxia-ischemia. These imaging findings, coupled with clinical features consistent with perinatal hypoxic-ischemic insult(s), warrant the specific designation of neonatal HIE.

[Cerebral palsy and perinatal asphyxia (II--Medicolegal implications and prevention)]

Obstetric litigation is a growing problem in developed countries and its escalating cost together with increasing medical insurance premiums is a major concern for maternity service providers, leading to obstetric practice cessation by many practitioners. Fifty-four to 74 % of claims are based on cardiotocographic (CTG) abnormalities and their interpretation followed by inappropriate or delayed reactions. A critical analysis is performed about the nine criteria identified by the American College of Obstetricians and Gynecologists and the American Academy of Pediatrics in their task force on Neonatal Encephalopathy and Cerebral Palsy: four essential criteria defining neonatal asphyxia and five other suggesting an acute intrapartum event sufficient to cause cerebral palsy in term newborns. The importance of placental histologic examination is emphasized in order to confirm sudden catastrophic events occurring before or during labor or to detect occult thrombotic processes affecting the fetal circulation, patterns of decreased placenta reserve and adaptative responses to chronic hypoxia. It may also exclude intrapartum hypoxia by revealing some histologic patterns typical of acute chorioamnionitis and fetal inflammatory response or compatible with metabolic diseases. Magnetic resonance imaging (MRI) of the infant's damaged brain is very contributive to elucidate the mechanism and timing of asphyxia in conjunction with the clinical picture, by locating cerebral injuries predominantly in white or grey matter. Intrapartum asphyxia is sometimes preventable by delivering weak fetuses by cesarean sections before birth, by avoiding some "sentinel" events, and essentially by responding appropriately to CTG anomalies and performing an efficient neonatal resuscitation. During litigation procedures, it is necessary to have access to a readable CTG, a well-documented partogram, a complete analysis of umbilical cord gases, a placental pathology and an extensive clinical work-up of the newborn infant including cerebral MRI. Malpractice litigation in obstetric care can be reduced by permanent CTG education, respect of national CTG guidelines, use of adjuncts such as fetal blood sampling for pH or lactates, regular review of adverse events in Clinical Risk Management (CRM) groups and periodic audits about low arterial cord pH in newborns, admission to neonatal unit, the need for assisted ventilation and the decision-to-delivery interval for emergency operative deliveries. Considering the fast occurrence of fetal cerebral hypoxic injuries, and thus despite an adequate management, many intrapartum asphyxias will not be preventable. Conversely, well-documented hypoxic-ischemic brain insults during the antenatal period do not automatically exclude intrapartum suboptimal obstetric care.

Intrapartum electronic fetal heart rate monitoring and the identification of metabolic acidosis and hypoxic-ischemic encephalopathy

OBJECTIVE

The purpose of this study was to determine whether electronic fetal monitoring can identify fetuses with metabolic acidosis and hypoxic-ischemic encephalopathy.

STUDY DESIGN

The cases were 107 nonanomalous chromosomally normal fetuses with an umbilical arterial pH < 7.0 and base excess < or = 12 mmol/L. Controls were the subsequent delivery that was matched by gestational age and mode of delivery. The last hour of electronic fetal monitoring before delivery was evaluated by 3 obstetricians who were blinded to outcome.

RESULTS

Cases had a significant increase in late and prolonged decelerations/hour and late decelerations/contractions. Those fetuses with hypoxic-ischemic encephalopathy had significant increases in bradycardia, decreased variability, and nonreactivity but no difference in late or variable decelerations/hour. For the identification of hypoxic-ischemic encephalopathy, the sensitivity, specificity, and positive and negative predictive values were 15.4%, 98.9%, 66.7%, and 89.4%, respectively, for bradycardia; 53.8%, 79.8%, 26.9%, and 92.6%, respectively, for decreased variability; 92.3%, 61.7%, 2.7%, and 82.9%, respectively, for nonreactivity; and 7.7%, 98.9%, 50.0%, and 88.6%, respectively, for all 3 abnormalities combined.

CONCLUSION

Fetal metabolic acidosis and hypoxic-ischemic encephalopathy are associated with significant increases in electronic fetal monitoring abnormalities, but their predictive ability to identify these conditions is low.

Medical legal issues in fetal monitoring

Despite almost universal fetal monitoring during labor, debates over its role and benefits persist in the medical community and in obstetric negligence lawsuits. Irrespective, there is widespread agreement that improvement in perinatal outcome is possible and that the events of labor contribute significantly to perinatal hazards. Timely application and proper interpretation of the fetal heart rate pattern in concert with evaluations of the maternal condition and the feasibility of safe vaginal delivery permit an evaluation of the quality of care and the preventability of fetal injury whether in peer review or in malpractice cases.