Prevalence of bradycardia in 4876 newborns in the first minute after birth and association with positive pressure ventilation: a population-based cross-sectional study

Objective To determine the prevalence of bradycardia in the first minute after birth and association with positive pressure ventilation (PPV).Method A population-based cross-sectional study was conducted from June 2019 to December 2021 at Stavanger University Hospital, Norway. Parents consented to participation during pregnancy, and newborns >= 28 weeks' gestation were included at birth. Heart rate (HR) was captured immediately after birth and continuously for the first minute(s). Time of birth was registered on a tablet. Provision of PPV was captured using video.Results Of 4876 included newborns, 164 (3.4%) did not breathe (two-thirds) or breathed ineffectively (one-third) and received PPV at birth. HR in the first minute had a wide distribution. The prevalence of first measured HR <100 and <60 beats/minute at median 16 s was 16.3% and 0.6%, respectively. HR increased in most cases. At 60 s, 3.7% had HR <100 beats/minute, of which 82% did not require PPV. In total, 25% of newborns had some registered HR <100 beats/minute during the first minute, of which 95% did not require PPV. Among newborns who received PPV, 76% and 62% had HR >= 100 beats/minute at 60 s and at start PPV, respectively.Conclusion Bradycardia with HR <100 bpm in the first minute of life was frequent, but mostly self-resolved. Among the 4% of newborns that remained bradycardic at 60 s, only 20% received PPV. Two-thirds of resuscitated newborns had HR >= 100 beats/minute at start PPV. None of the ventilated newborns were breathing adequately at start PPV.

Automated summary

This study aimed to determine the prevalence of bradycardia in newborns in the first minute after birth and its association with positive pressure ventilation (PPV). The study found that 16.3% of newborns had a heart rate lower than 100 beats/minute in the first minute, but most cases resolved on their own. Only 4% of newborns remained bradycardic at 60 seconds, and only 20% of them received PPV.