What is the Apgar Score?
Apgar is an acronym for Appearance (skin color), Pulse (heart rate), Grimace (reflex irritability), Activity (muscle tone), and Respiration. It was initially created in 1952 as a mnemonic to evaluate the health of a newborn infant. With time, the Apgar score became a standard score measuring system to assess the health of all newly borns.
The Apgar test is generally done at 1 and 5 minutes after birth. If the score is low, it may be repeated later for reevaluation. Scores of 7 and above are considered normal; 4 to 6, fairly low; and 3 and below are regarded as severely low and indicate the need for urgent resuscitative measures. Scores are calculated from 0 to 2 for each of the five variables.
A low score on the 1-minute mark may show that the neonate requires medical attention, but does not necessarily indicate a long-term problem, particularly if the score improves at the 5-minute mark. An Apgar score that remains below 3 at later times, such as 10, 15, or 30 minutes, may indicate more serious neurological impairment, including a small but significant increase in the risk of cerebral palsy. The main purpose of calculating the Apgar score is to evaluate the need for urgent medical care and not to determine chronic health issues.
Is the Apgar Score effective in assessing the health of preterm infants?
Although widely used in term infants, its efficacy in evaluating preterm infants has been debated by clinicians. Pediatricians are concerned that immature infants may all present with low scores in comparison to term infants. In order to evaluate the value of Apgar score in preterm infants, researchers have conducted a study to predict the rate of survival in preterm infants based solely on Apgar score.
Research on Preterm Infants
By analyzing data from a Swedish nationwide register, the researchers included 113,000 morphologically normal preterm infants born between 22 to 36 weeks of pregnancy between 1992 and 2016. All the infants were assessed using their Apgar scores at five minutes followed by at ten minutes. Analyses for preterm infants born at 22-24, 25-27, 28-31, 32-34, and 35-36 gestational weeks were done separately.
Among the 113,000 total preterm infants, 1,986 preterm infants did not survive beyond the neonatal period. Not surprisingly, the mortality rate was significantly higher with a shorter duration of pregnancy with a mortality rate at 0.2 percent for infants born at 36 weeks to 76.5 percent for those born at 22 weeks.
However, apart from the gestational period Apgar score was also indicative of mortality rate with lower Apgar score infants having a higher mortality rate regardless of their gestational age. Furthermore, improvement in Apgar score from five to ten minutes was associated with an improved survival rate.
“Our results show the importance of registering Apgar score also in preterm infants,” says Sven Cnattingius, senior professor at the Department of Medicine, Solna, Karolinska Institutet, and the study’s corresponding author. “It is important that infants with reduced scores receive full clinical attention regardless of gestational age.”
“Heart activity and breathing are the cornerstones of the Apgar assessment,” says co-author Stefan Johansson, associate professor at the Department of Medicine, Solna, Karolinska Institutet, and neonatologist at the Sachsska children and youth hospital in Stockholm.
“Our research indicates that the chance of survival increases the better you are at stabilizing the premature baby’s circulation and breathing immediately after birth.”
Besides the Apgar score and gestational age, the researchers also included other factors in the study such as the age of the mother, birth weight, blood pressure, comorbidities, etc in order to eliminate confounding factors. The research concluded that the Apgar score is equally effective for preterm infants as it is for term infants.