Observational study comparing heart rate in crying and non-crying but breathing infants at birth

BMJ Paediatr Open. 2023 Apr;7(1):e001886. doi: 10.1136/bmjpo-2023-001886.


Background: Stimulating infants to elicit a cry at birth is common but could result in unnecessary handling. We evaluated heart rate in infants who were crying versus non-crying but breathing immediately after birth.

Methods: This was single-centre observational study of singleton, vaginally born infants at ≥33 weeks of gestation. Infants who were crying or non-crying but breathing within 30 s after birth were included. Background demographic data and delivery room events were recorded using tablet-based applications and synchronised with continuous heart rate data recorded by a dry-electrode electrocardiographic monitor. Heart rate centile curves for the first 3 min of life were generated with piecewise regression analysis. Odds of bradycardia and tachycardia were compared using multiple logistic regression.

Results: 1155 crying and 54 non-crying but breathing neonates were included in the final analyses. There were no significant differences in the demographic and obstetric factors between the cohorts. Non-crying but breathing infants had higher rates of early cord clamping <60 s after birth (75.9% vs 46.5%) and admission to the neonatal intensive care unit (13.0% vs 4.3%). There were no significant differences in median heart rates between the cohorts. Non-crying but breathing infants had higher odds of bradycardia (heart rate <100 beats/min, adjusted OR 2.64, 95% CI 1.34 to 5.17) and tachycardia (heart rate ≥200 beats/min, adjusted OR 2.86, 95% CI 1.50 to 5.47).

Conclusion: Infants who are quietly breathing but do not cry after birth have an increased risk of both bradycardia and tachycardia, and admission to the neonatal intensive care unit.

Trial registration number: ISRCTN18148368.

Keywords: neonatology; physiology; resuscitation.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bradycardia* / diagnosis
  • Bradycardia* / epidemiology
  • Female
  • Heart Rate / physiology
  • Humans
  • Infant
  • Infant, Newborn
  • Parturition*
  • Pregnancy
  • Regression Analysis
  • Respiration