Clinician Identification of Birth Asphyxia Using Intrapartum Cardiotocography Among Neonates With and Without Encephalopathy in New Zealand

Abstract

IMPORTANCE Despite improvements in antenatal care and increasing cesarean delivery rates, birth asphyxia leading to neonatal encephalopathy (NE) continues to contribute to neonatal death and long-term neurodevelopmental disability. Cardiotocography (CTG) has been used in labor for several decades to detect a stressed fetus so that delivery can be expedited and NE avoided. OBJECTIVE To investigate whether experienced clinicians can detect and respond to abnormal readings from CTGs during the penultimate hour before birth in infants with moderate to severe NE but no acute peripartum event. DESIGN, SETTING, AND PARTICIPANTS This case-control study included 10 practicing obstetricians and midwives at maternity hospitals in New Zealand. Participants, who were masked to the perinatal outcome, were asked to assess CTG tracings from 35 neonates with NE and evidence of birth hypoxia (ie, cases) and 105 neonates without NE or birth hypoxia (ie, controls), all of whom were born in 2010 to 2011. Data analysis was conducted from May to December 2017. EXPOSURES Brief clinical details and 1 hour of CTG tracings from the penultimate hour before birth were provided for each baby. Clinicians assessed the CTG tracings and recommended a plan. MAIN OUTCOMES AND MEASURES Intra-assessor and interassessor agreement on CTG findings and action plans as well as sensitivity (ie, detection of NE) and specificity (ie, ruling out those without NE) for the assessment of abnormal CTG readings leading to immediate action (ie, fetal blood sample or immediate delivery) were reported. RESULTS A total of 35 infants (mean [SD] gestational age, 40 [1.4] weeks; 16 [45.7%] cesarean deliveries) were designated cases, and 105 infants (mean [SD] gestational age, 39.4 [1.2] weeks; 22 [21.0%] cesarean deliveries) were designated controls. No infants had congenital anomalies. The mean (range) sensitivity for detection of abnormal CTG results and for recommending immediate action for all assessors was 75% (63%-91%) and 41% (23%-57%), respectively, with a mean (range) specificity of 67% (53%-77%) and 87% (65%-99%), respectively. A sensitivity analysis including only assessors with 80% or more interassessor agreement only differed from the main analysis by 6% or less (mean [range] sensitivity for detection, 76% [63%-91%]; sensitivity for action plan, 36% [25%-49%]; specificity for detection, 71% [53%-77%]; and specificity for action plan, 93% [88%-99%]). CONCLUSIONS AND RELEVANCE Experienced clinicians detected 3 of 4 infants who were subsequently diagnosed with NE. Action to expedite delivery was recommended for more than 40% (continued) Key Points Question Can experienced clinicians detect and manage abnormal cardiotocograph readings during the penultimate hour before birth among infants with moderate to severe neonatal encephalopathy but no acute peripartum event? Findings In this case-control study of 35 infants with neonatal encephalopathy and 105 without, experienced obstetricians and midwives were able to detect 3 of 4 neonates who were subsequently diagno...

Effect of intra-partum Oxytocin on neonatal encephalopathy: a systematic review and meta-analysis

“…We identified seven studies following full text screening, of which one had its data collected during a previous community-based cluster randomised controlled trial. These seven studies included neonatal encephalopathy as an outcome, of which 6 were case controls and 1 was a cluster randomised trial [ 11 – 17 ] (Fig. 1 ).…”

“…Mullany et al [ 16 ] considered infants to have intrapartum-related moderate-severe neonatal encephalopathy provided they experienced intrapartum-related neonatal respiratory depression resulting in death of seizures and 2 of the following: lethargy, poor suck or respiratory rate less than 40 breaths per minute, observed anytime during the first 7 days of life. Lastly, Farquhar [ 11 ] et al describe the study to include only moderate and severe encephalopathic babies according to New Zealand’s Neonatal Encephalopathy Working Group of the Perinatal and Maternal Mortality Review Committee (PMMRC). The Committee defines neonatal encephalopathy as a clinically defined syndrome of disturbed neurological function within the first week of life in term infants (i.e., 37 weeks or older), manifested by difficulty initiating and maintaining respiration, depression of tone and reflexes, subnormal level of consciousness, and often, seizures.…”

“…Pooled data from HIC studies ( Farquhar et al, Hayes et al and Milsom et al) [ 11 – 13 ] revealed that 24, 40 and 62% of mothers that were administered Oxytocin gave birth to an encephalopathic infant, respectively. Moreover, the four studies looking at LMICs ( Ellis et al , Futrakul et al , Mullany et al , Tann et al) [ 14 – 17 ] reported the same event occurring in 27, 39, 3 and 49% of infants following intra-partum Oxytocin administration.…”

Estimation and Discriminability of Doppler Ultrasound Fetal Heart Rate Variability Measures

“…Clinicians assess the risk of acidosis and HIE by visually monitoring the EFM for characteristic FHR patterns such as the baseline, accelerations, and decelerations ( American College of Obstetricians and Gynecologists, 2014 ; Lear et al, 2018 ). Nevertheless, visual assessment of FHR tracings has low specificity and sensitivity as well as high intra- and inter-observer variability ( Farquhar et al, 2020 ). The application of computerized analysis to quantify FHR signals has been proposed to reduce intra- and inter-observer variability ( Keith and Greene, 1994 ).…”

Electronic Fetal Monitoring—Imperfect but Opportunities for Improvement

“…There appear to be limitations for each of these steps.Farquhar and colleagues 8 designed a case-control study to examine whether abnormal readings can be identified on the continuous fetal heart rate monitoring strip, also known as a cardiotocograph (CTG). 8 The cases were all of neonatal encephalopathy in which there was at least 1 hour of CTG available in the penultimate hour before delivery. The authors excluded cases that included an acute peripartum event immediately prior to delivery as well as cases with a likely source of the neonatal encephalopathy that preceded the labor and delivery.…”