Five-minute Apgar score and outcomes in neonates of 24-28 weeks' gestation

Five-minute Apgar score and risk of neonatal mortality, severe neurological morbidity and severe non-neurological morbidity in term infants - an Australian population-based cohort study

Background

The aim of this study was to ascertain risks of neonatal mortality, severe neurological morbidity and severe non-neurological morbidity related to the 5-min Apgar score in early term (37+0-38+6 weeks), full term (39+0-40+6 weeks), late term (41+0-41+6 weeks), and post term (≥42+0 weeks) infants.

Methods

This was a retrospective cohort study of 941,221 term singleton births between 2000 and 2018 in Queensland, Australia. Apgar scores at 5-min were categorized into five groups: Apgar 0 or 1, 2 or 3, 4-6, 7 or 8 and 9 or 10. Gestational age was stratified into 4 groups: Early term, full term, late term and post term. Three specific neonatal study outcomes were considered: 1) Neonatal mortality 2) Severe neurological morbidity and 3) Severe non-neurological morbidity. Poisson multivariable regression models were used to determine relative risk ratios for the effect of gestational age and Apgar scores on these severe neonatal outcomes. We hypothesized that a low Apgar score of <4 was significantly associated with increased risks of neonatal mortality, severe neurological morbidity and severe non-neurological morbidity.

Findings

Of the study cohort, 0.04% (345/941,221) were neonatal deaths, 0.70% (6627/941,221) were infants with severe neurological morbidity and 4.3% (40,693/941,221) had severe non-neurological morbidity. Infants with Apgar score <4 were more likely to birth at late term and post term gestations and have birthweights <3rd and <10th percentiles. The adjusted relative risk ratios (aRRR) for neonatal mortality and severe neurological morbidity were highest in the Apgar 0 or 1 cohort. For infants in the Apgar 0 or 1 group, neonatal mortality increased incrementally with advancing term gestation: early term (aRRR 860.16, 95% CI 560.96, 1318.94, p < 0.001); full term (aRRR 1835.77, 95% CI 1279.48, 2633.91, p < 0.001); late term (aRRR 1693.61, 95% CI 859.65, 3336.6, p < 0.001) and post term (aRRR 2231.59, 95% CI 272.23, 18293.07, p < 0.001) whilst severe neurological morbidity decreased as gestation progressed: early term (aRRR 158.48, 95% CI 118.74, 211.51, p < 0.001); full term (aRRR 112.99, 95% CI 90.56, 140.98, p < 0.001); late term (aRRR 87.94, 95% CI 67.09, 115.27, p < 0.001) and post term (aRRR 52.07, 95% CI 15.17, 178.70, p < 0.001). Severe non-neurological morbidity was greatest in the full term, Apgar 2-3 cohort (aRRR 7.36, 95% CI 6.2, 8.74, p < 0.001).

Interpretation

A 5-min Apgar score of <4 was prognostic of neonatal mortality, severe neurological morbidity, and severe non-neurological morbidity in infants born >37 weeks' gestation with the risk greatest in the early term cohort.

Funding

National Health and Medical Research Council and Mater Foundation.

Factors associated with the increased incidence of necrotising enterocolitis in extremely preterm infants in Sweden between two population-based national cohorts (2004-2007 vs 2014-2016)

OBJECTIVE

To investigate potential risk factors behind the increased incidence of necrotising enterocolitis (NEC) in Swedish extremely preterm infants.

DESIGN

Registry data from two population-based national cohorts were studied. NEC diagnoses (Bell stage ≥II) were validated against hospital records.

PATIENTS

All liveborn infants <27 weeks of gestation 2004-2007 (n=704) and 2014-2016 (n=895) in Sweden.

MAIN OUTCOME MEASURES

NEC incidence.

RESULTS

The validation process resulted in a 28% reduction of NEC cases but still confirmed a higher NEC incidence in the later epoch compared with the earlier (73/895 (8.2%) vs 27/704 (3.8%), p=0.001), while the composite of NEC or death was lower (244/895 (27.3%) vs 229/704 (32.5%), p=0.022). In a multivariable Cox regression model, censored for mortality, there was no significant difference in early NEC (0-7 days of life) between epochs (HR=0.9 (95% CI 0.5 to 1.9), p=0.9), but being born in the later epoch remained an independent risk factor for late NEC (>7 days) (HR=2.7 (95% CI 1.5 to 5.0), p=0.001). In propensity score analysis, a significant epoch difference in NEC incidence (12% vs 2.8%, p<0.001) was observed only in the tertile of infants at highest risk of NEC, where the 28-day mortality was lower in the later epoch (35% vs 50%, p=0.001). More NEC cases were diagnosed with intramural gas in the later epoch (33/73 (45.2%) vs 6/26 (23.1%), p=0.047).

CONCLUSIONS

The increase in NEC incidence between epochs was limited to cases occurring after 7 days of life and was partly explained by increased survival in the most extremely preterm infants. Misclassification of NEC is common.

Apgar Score and Neurodevelopmental Outcomes at Age 5 Years in Infants Born Extremely Preterm

Importance

The Apgar score is used worldwide as an assessment tool to estimate the vitality of newborns in their first minutes of life. Its applicability to estimate neurodevelopmental outcomes in infants born extremely preterm (EPT; <28 weeks' gestation) is not well established.

Objective

To investigate the association between the Apgar score and neurodevelopmental outcomes in infants born EPT.

Design, Setting, and Participants

This cohort study was conducted using data from the Effective Perinatal Intensive Care in Europe-Screening to Improve Health in Very Preterm Infants in Europe (EPICE-SHIPS) study, a population-based cohort in 19 regions of 11 European countries in 2011 to 2012. Clinical assessments of cognition and motor function at age 5 years were performed in infants born EPT and analyzed in January to July 2023.

Exposures

Apgar score at 5 minutes of life categorized into 4 groups (0-3, 4-6, 7-8, and 9-10 points).

Main Outcomes and Measures

Cognitive and motor outcomes were assessed using the Wechsler Preschool and Primary Scale of Intelligence test of IQ derived from locally normed versions by country and the Movement Assessment Battery for Children-Second Edition. Parents additionally provided information on communication and problem-solving skills using the Ages and Stages Questionnaire, third edition (ASQ-3). All outcomes were measured as continuous variables.

Results

From the total cohort of 4395 infants born EPT, 2522 infants were live born, 1654 infants survived to age 5 years, and 996 infants (478 females [48.0%]) followed up had at least 1 of 3 outcome measures. After adjusting for sociodemographic variables, perinatal factors, and severe neonatal morbidities, there was no association of Apgar score with IQ, even for scores of 3 or less (β = -3.3; 95% CI, -10.5 to 3.8) compared with the score 9 to 10 category. Similarly, no association was found for ASQ-3 (β = -2.1; 95% CI, -24.6 to 20.4). Congruent results for Apgar scores of 3 or less were obtained for motor function scores for all children (β = -4.0; 95% CI, -20.1 to 12.1) and excluding children with a diagnosis of cerebral palsy (β = 0.8, 95% CI -11.7 to 13.3).

Conclusions and Relevance

This study found that low Apgar scores were not associated with longer-term outcomes in infants born EPT. This finding may be associated with high interobserver variability in Apgar scoring, reduced vitality signs and poorer responses to resuscitation after birth among infants born EPT, and the association of more deleterious exposures in the neonatal intensive care unit or of socioeconomic factors with greater changes in outcomes during the first 5 years of life.