Expert review--identification of intra-partum fetal compromise

Fetal monitoring technologies for the detection of intrapartum hypoxia - challenges and opportunities

Intrapartum fetal hypoxia is related to long-term morbidity and mortality of the fetus and the mother. Fetal surveillance is extremely important to minimize the adverse outcomes arising from fetal hypoxia during labour. Several methods have been used in current clinical practice to monitor fetal well-being. For instance, biophysical technologies including cardiotocography, ST-analysis adjunct to cardiotocography, and Doppler ultrasound are used for intrapartum fetal monitoring. However, these technologies result in a high false-positive rate and increased obstetric interventions during labour. Alternatively, biochemical-based technologies including fetal scalp blood sampling and fetal pulse oximetry are used to identify metabolic acidosis and oxygen deprivation resulting from fetal hypoxia. These technologies neither improve clinical outcomes nor reduce unnecessary interventions during labour. Also, there is a need to link the physiological changes during fetal hypoxia to fetal monitoring technologies. The objective of this article is to assess the clinical background of fetal hypoxia and to review existing monitoring technologies for the detection and monitoring of fetal hypoxia. A comprehensive review has been made to predict fetal hypoxia using computational and machine-learning algorithms. The detection of more specific biomarkers or new sensing technologies is also reviewed which may help in the enhancement of the reliability of continuous fetal monitoring and may result in the accurate detection of intrapartum fetal hypoxia.

A Detailed Review of Critical Care Considerations for the Pregnant Cardiac Patient

Maternal cardiovascular disease is a leading cause of maternal death worldwide and recently, maternal mortality has increased secondary to cardiovascular causes. Maternal admissions to critical care encompass 1%-2% of all critical care admissions, and although not common, the management of the critically ill pregnant patient is complex. Caring for the critically ill pregnant cardiac patient requires integration of pregnancy-associated physiologic changes, understanding pathophysiologic disease states unique to pregnancy, and a multidisciplinary approach to timing around delivery as well as antenatal and postpartum care. Herein we describe cardiorespiratory changes that occur during pregnancy and the differential diagnosis for cardiorespiratory failure in pregnancy. Cardiorespiratory diseases that are either associated or exacerbated by pregnancy are highlighted with emphasis on perturbations secondary to pregnancy and appropriate management strategies. Finally, we describe general management of the pregnant cardiac patient admitted to critical care.

[Normal childbirth: Physiologic labor support and medical procedures. Guidelines of the French National Authority for Health (HAS) with the collaboration of the French College of Gynaecologists and Obstetricians (CNGOF) and the French College of Midwives (CNSF) - Initial assessment on admission and fetal monitoring during labor]

OBJECTIVES

The purpose of this literature's review is to provide recommendations for measures to assess fetal "well-being" at admission and during labor in order to identify a non-reassuring fetal condition.

METHODS

Consultation of the Medline database, and of national and international guidelines.

RESULTS

Two fetal heart rate monitoring techniques are available at admission and during labor. In comparison with intermittent auscultation (AI), continuous cardiotocography (CTG) monitoring was associated, in a meta-analysis involving 13 trials including more than 37,000 women, with a reduction in RR neonatal seizures by half. Relative risk (RR)=0.50 with a 95% CI [0.31-0.80] without significant difference objectified with respect to cerebral palsy RR=1.75 95% CI [0.84-3.63]. In contrast, a significant increase in cesarean sections was associated with continuous CTG RR=1.63 95% CI [1.29-2.07] and women were also at greater risk for operative vaginal delivery RR=1.15 95% CI [1.01-1.33]. Current results are insufficient to demonstrate the actual impact of surveillance methods (continuous or discontinuous) on the overall perinatal mortality rate. Larger randomized trials remain to be conducted.

CONCLUSION

The systematic search for the confirmation of the reassuring character of the fetal state at admission and during labor makes it possible to identify intrapartum hypoxic events.

Intrapartum fetal monitoring and perinatal risk factors of neonatal hypoxic-ischemic encephalopathy

BACKGROUND

Neonatal hypoxic-ischemic encephalopathy (HIE) in term infants, is a major cause of neonatal mortality and severe neurologic disability.

OBJECTIVES

To identify in labor fetal monitoring characteristic patterns and perinatal factors associated with neonatal HIE.

STUDY DESIGN

Single-center retrospective case-control study between 2010 and 2017. Cases clinically diagnosed with neonatal HIE treated by therapeutic hypothermia according to strict criteria (HIE-TH) were compared to a group of neonates born in the same period, gestational age-matched diagnosed with fetal distress according to fetal monitoring interpretation that was followed by prompt delivery, without subsequent HIE or therapeutic hypothermia (No-HIE). The primary outcome of the study was the electronic fetal monitoring (EFM) pattern during 60 min prior to delivery; the secondary outcome was the identification of perinatal associated factors.

RESULTS

54 neonates with HIE were treated by therapeutic hypothermia. EFM parameters most predictive of HIE-TH were indeterminate baseline heart rate OR = 47.297, 95% (8.17-273.76) p < 0.001, bradycardia OR = 15.997 95% (4.18-61.18) p < 0.001, low variability OR = 10.224, 95% (2.71-38.45) p < 0.001, higher baseline of the fetal heart rate calculated for each increment of 1 BPM OR = 1.0547, 95% (1.001-1.116) p = 0.047. Rupture of a previous uterine cesarean scar and placental abruption were characteristic of the HIE-TH group 14.8% vs. 1% p < 0.05; and 16.7% vs. 6% p < 0.05, respectively. Adverse neonatal outcomes also differed significantly: HIE-TH had a higher rate of neonatal seizures 46.2% vs. 0% p < 0.001 and mortality 7.7% vs. 0% p < 0.001.

CONCLUSIONS

Characteristic fetal monitoring pattern prior to delivery together with acute obstetric emergency events are associated with neonatal HIE, neurological morbidity, and mortality.

[Neonatal arterial ischemic stroke in term or near-term newborns: prevalence and risk factors]

The general designation ischemic perinatal stroke includes several disease states that differ in pathophysiology, timing of occurrence and presentation. While it seems logical to assume that their prevalence and their risk factors depend primarily on the considered type of stroke, most studies used inconsistent definitions or included heterogeneous populations, which limits their accuracy. Given these biases, the French Society of Neonatology and the French Centre for Paediatric Stroke wished to update the knowledge in this domain, focusing on a specific form of perinatal stroke, i.e neonatal arterial ischemic stroke (NAIS) in term or near term newborns. A comprehensive analysis of published epidemiological data was dedicated to the following issues: Is the prevalence of NAIS well defined from epidemiological studies? What are the best recognized risk factors and is it possible to delineate a maternal and fetal population at risk for this condition? On July 31, 2015 a total of four hospitalized-based and five population-based studies, and six case-control studies were found. The conclusions are the following: The prevalence of NAIS in term or near term newborns varies from 6 to 17/100,000 live births (level of evidence 2). NAIS represents a half of total ischemic perinatal strokes (i.e. including those with delayed presentation as well) and one fourth of perinatal strokes (i.e. including cerebral haemorrhage stroke as well). Four sets of risk factors are consistent across different studies (level of evidence 3): (1) male sex, (2) obstetrical determinants (first pregnancy, caesarean section), and two peripartum complications: (3) intrapartum hypoxia and (4) materno-fetal/neonatal infection. Bacterial meningitis, cardiac disorders/procedures and invasive care such as extra-corporeal circulation carry a risk of NAIS as well. A registry could help refining epidemiological descriptive data. It could also be used to develop etiological studies focusing on pathophysiological hypotheses derived from the identified aforementioned risk factors.

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.

The relationship between maternal placental growth factor levels and intrapartum fetal compromise

INTRODUCTION

Whilst some cases of intrapartum fetal compromise are the result of unpredictable catastrophic events, the majority arise from an unrecognised reduction in feto-placental reserve in otherwise healthy pregnancies. There is currently no reliable technique prior to labour that identifies the at-risk fetus. We aimed to investigate the relationship between maternal levels of serum placental growth factor (PlGF) and intrapartum fetal compromise in term pregnancies prior to labour. Secondary outcomes were caesarean delivery for intrapartum fetal compromise and adverse neonatal outcomes.

METHODS

A blinded, prospective, cross sectional study set at Mater Mother's Hospital, Brisbane, Australia. Maternal PlGF concentration was assessed fortnightly from 36 weeks until delivery in 378 low-risk pregnant women. Antenatal and intrapartum care was managed according to local protocols and guidelines, and intrapartum and neonatal outcomes were recorded.

RESULTS

Pregnancies that developed intrapartum fetal compromise had lower PlGF than those that did not. PlGF concentration was also lower amongst pregnancies that developed intrapartum fetal heart rate abnormalities, were delivered with abnormal cord gases or Apgar ≤7 at 5 min. Additionally, PlGF levels were lower in pregnancies with an adverse composite neonatal outcome.

DISCUSSION

Lower maternal PlGF concentration is associated with intrapartum fetal compromise and poorer condition of the newborn. Maternal PlGF levels may be useful as a component of a risk stratification tool for intrapartum fetal compromise in apparently 'low risk' term pregnancies prior to labour.