What is the significance and interpretation of the Apgar (Appearance, Pulse, Grimace, Activity, Respiration) score in newborns?

The Apgar Score: Significance and Interpretation in Newborns

The Apgar score is a standardized assessment tool that describes the condition of newborns immediately after birth and provides a mechanism to record fetal-to-neonatal transition, but it should not be used alone to predict individual mortality or adverse neurologic outcomes. 1

Components and Scoring

The Apgar score evaluates five physiological parameters:

• Appearance (skin color)
• Pulse (heart rate)
• Grimace (reflex irritability)
• Activity (muscle tone)
• Respiration (respiratory effort)

Each component is scored 0,1, or 2, with a total possible score of 10. The assessment is typically performed at 1 minute and 5 minutes after birth, with additional assessments at 10,15, and 20 minutes if the score remains low.

Clinical Significance

Interpretation of Scores

• 1-minute Apgar score: Reflects the immediate need for resuscitation

  • Score 0-3: Indicates severe distress
  • Score 4-6: Indicates moderate difficulty
  • Score 7-10: Indicates good to excellent condition

• 5-minute Apgar score: More predictive of outcomes at population level

  • Score 0-3: Correlates with increased neonatal mortality risk in populations
  • Score 7-10: Generally indicates good adaptation to extrauterine life

Prognostic Value

• A 1-minute Apgar score of 0-3 does not predict individual infant outcomes 1
• A 5-minute Apgar score of 0-3 correlates with neonatal mortality in large populations but cannot predict individual future neurologic dysfunction 1
• Low 5-minute Apgar scores (less than 5) confer an increased relative risk of cerebral palsy (20-100 fold higher compared to infants with scores of 7-10) 1
• The population risk of poor neurologic outcomes increases when the Apgar score is 3 or less at 10,15, and 20 minutes 1

Clinical Actions Based on Apgar Scores

• When a newborn has an Apgar score of 5 or less at 5 minutes:

  • Obtain umbilical arterial blood gas samples from a clamped section of the umbilical cord 1
  • Consider submitting the placenta for pathologic examination 1
  • Monitor for signs of hypoxic-ischemic injury 2

• For persistently low scores (≤3) at 10,15, or 20 minutes:

  • Consider more comprehensive evaluation for potential hypoxic-ischemic injury, including neuroimaging and electroencephalography 2

Limitations and Caveats

• The Apgar score represents the infant's physiologic condition at one point in time and includes subjective components 1

• Multiple factors can influence the score:

  • Maternal sedation or anesthesia
  • Congenital malformations
  • Gestational age
  • Trauma
  • Interobserver variability 1

• Elements such as tone, color, and reflex irritability are subjective and partially depend on the infant's physiologic maturity 1

• The Apgar score alone cannot be considered evidence of or a consequence of asphyxia 1

• Normal transition variations may affect the score (e.g., lower initial oxygen saturations in the first few minutes are normal) 1

Recent Research Insights

• Studies show that heart rate, respiratory effort, and color components at 5 minutes are independently associated with increased risks of neonatal mortality 3
• In very preterm infants (≤31 weeks), the Apgar score may be a better predictor of neonatal mortality than in infants with longer gestations 3
• Factors associated with low 5-minute Apgar scores in cesarean deliveries include:
  • Low birth weight (<2.5 kg)
  • Prolonged skin incision to delivery time
  • Pregnancy-induced hypertension
  • Antepartum hemorrhage
  • General anesthesia
  • Meconium-stained amniotic fluid
  • Emergency cesarean section 4

Best Practices for Apgar Score Use

• Use the expanded Apgar score reporting form that accounts for concurrent resuscitative interventions 1
• Be consistent in assigning scores during resuscitation 1
• Recognize that most infants with low Apgar scores will not develop cerebral palsy 1
• Use Apgar scores as part of a comprehensive assessment, not as the sole determinant for diagnosis or prognosis 1
• Consider monitoring trends in low Apgar scores at a delivery service level to identify needs for educational programs and improvements in perinatal care systems 1