Apgar score at 10 minutes and adverse outcomes among low-risk pregnancies

Abstract

Objective Among low-risk pregnancies, we ascertained the association between 10-minute Apgar score and adverse outcomes of newborn infants. Method We conducted a retrospective cohort study using the U.S. vital statistics datasets (2011–2018), which included live births from low-risk women with non-anomalous singleton gestations who delivered at 37–41 weeks. When a newborn infant had an abnormal 5-minute Apgar score (0–5), a 10-minute Apgar score was documented in the birth certificate. Apgar score at 10 min was categorized as low (0–3), moderate (4–6), and normal (7–10). The primary outcome was composite neonatal adverse outcome. The secondary outcomes were individual neonatal adverse outcomes and infant mortality. Multivariable Poisson regression analyses were used to estimate the association between 10-minute Apgar score and adverse outcomes (using adjusted relative risk [aRR] and 95% confidence intervals [CI]). Results Of 31.5 million live births delivered (2011–2018), 111,163 (0.4%) met inclusion criteria; of them, 74.2%, 20.7%, and 5.1% had normal, moderate, and low 10-minute Apgar scores, respectively. The overall composite neonatal adverse outcome was 100.6 per 1,000 live births and the risk was significantly higher among those with a moderate (aRR 3.19; 95% CI 3.06–3.31) or low 10-minute Apgar score (aRR 6.62; 95% CI 6.34–6.91) than with a normal 10-minute Apgar score. Infant mortality also showed a similar pattern. Newborn infants with improved Apgar scores from 5 to 10 min were associated with lower risks of the composite neonatal adverse outcome, as well as infant mortality, than those with scores that remained stable. Conclusion Among low-risk pregnancies, newborn infants with a lower 10-minute Apgar score were associated with a higher risk of adverse outcomes.