BACKGROUND AND PURPOSE:

• The clinical value of low Apgar scores is not well understood for preterm infants
• Cnattingius et al. (NEJM, 2020) examined the associations between the risk of neonatal death and Apgar scores at 5 and 10 minutes among preterm infants stratified according to gestational age

METHODS:

• Secondary analysis of a prospective cohort study
• Data source
  • Swedish Medical Birth Register
• Participants
  • Preterm infants (22w0d to 36w6d)
  • Born between 1992 and 2016
• Study design
  • Analyses were stratified according to gestational age
    • 22 to 24 weeks | 25 to 27 weeks | 28 to 31 weeks | 32 to 34 weeks | 35 weeks | 36 weeks
  • Reference group: Neonates with scores of 9 or 10
  • The authors estimated the following with respect to 5 and 10 minute Apgar scores
    • Adjusted relative risks (RR) of neonatal death
    • Absolute rate differences in neonatal mortality (excess number of neonatal deaths per 100 births)
•  Primary outcome
  • Neonatal mortality (death within first 27 days of life)

RESULTS:

• 113,300 preterm infants were included
  • Neonatal deaths: 1.8%
• Incidence of neonatal death ranges from
  • 36 weeks: 0.2%
  • 22 weeks: 76.5%
• In all gestational-age strata, lower Apgar scores were associated with both
  • Higher RRs of neonatal death
  • Greater absolute rate differences in neonatal mortality
• For infants born at 28 to 31 weeks, adjusted absolute rate differences according to the 5-minute Apgar score were as follows
  • Score 0 or 1: 51.7 (95% CI, 38.1 to 65.4)
  • Score 2 or 3: 25.5 (95% CI, 18.3 to 32.8)
  • Score 4 to 6: 7.1 (95% CI, 5.1 to 9.1)
  • Score 7 or 8: 1.2 (95% CI, 0.5 to 1.9)
• An increase in the Apgar score between 5 minutes and 10 minutes was associated with lower neonatal mortality compared to a stable Apgar scores
  • This finding was consistently seen even among neonates with normal Apgars (e.g., increase from 7 or 8 to 9 or 10)

CONCLUSION:

• Apgar scores at 5 and 10 minutes are predictive for neonatal survival in preterm infants
• There is a dose–response associations between Apgar score and risks of neonatal death
• The authors state

In this nationwide study, 5-minute and 10-minute Apgar scores and changes in the score between 5 minutes and 10 minutes were associated with neonatal mortality among preterm infants across gestational ages

Learn More – Primary Sources:

Apgar Score and Risk of Neonatal Death among Preterm Infants

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