Heart rate in newborns is associated with age, sex and maternal levothyroxine therapy.
Acta Paediatr
; 113(5): 973-979, 2024 05.
Article
em En
| MEDLINE
| ID: mdl-38305638
ABSTRACT
AIM:
To evaluate the definition and causes of neonatal bradycardias.METHODS:
This retrospective study included 135 term-born newborns referred for 24-hour Holter monitoring due to bradycardia. Bradycardia was defined as either a heart rate below 80 beats per minute (standard definition) or a heart rate below our recently published age-specific reference values for neonatal heart rate.RESULTS:
The mean (SD) age was 6.1 (1.3) days. With standard definition, 107 newborns (79%) had bradycardia, whereas only 20 (15%) had a minimum heart rate lower than the age-specific reference. Younger newborns had lower heart rates. Each day increased the minimum, mean and maximum heart rate by 1.8 (95% CI 1.0, 2.6), 4.2 (95% CI 3.0, 5.3) and 2.1 beats per minute (95% CI 0.3, 3.8), respectively. Male sex and maternal levothyroxine medication were negatively associated with the mean and maximum heart rate. None of the newborns had a cardiac cause for low heart rate.CONCLUSION:
Among term newborns with bradycardias, younger age, male sex and maternal levothyroxine medication were associated with a lower heart rate on Holter monitoring. Given the age-related increase in heart rate, the 80 beats per minute limit as a universal threshold for abnormal heart rate in newborns appears inappropriate.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Tipo de estudo:
Observational_studies
/
Risk_factors_studies
Limite:
Humans
/
Male
/
Newborn
Idioma:
En
Ano de publicação:
2024
Tipo de documento:
Article