Introduction:
The Apgar score is useful in evaluating the need for urgent medical care in newborns. However, the prognostic value as a risk factor for development of atopic diseases in childhood is unknown. 

Aims and objectives:
To investigate whether children with 5-minute-Apgar-scores within the normal range of 7-9 had higher risk of asthma, allergy, and eczema until age 6 years compared with children with an Apgar-score of 10. 

Methods:
This is a nationwide, register-based cohort study of all children born in Denmark between 2008 to 2019 with an Apgar-score of 7 to 10, divided into two groups (7-9 and 10). Using Cox regression, we calculated hazard ratios of developing asthma, allergic rhinitis, and eczema based on filled prescriptions and ICD-10 codes. Models were adjusted for sex, cesarean section, maternal smoking, maternal asthma, birth weight, and gestational age.

Results:
We included 400,761 children (195,663 (48.8%) girls) of whom 24.620 (6.1%) had an Apgar-score of 7-9 and 376.141 (93.9%) had a score of 10. Mean birth weight was 3482 g and 21% were delivered by cesarean section. Maternal smoking and maternal asthma were reported among 10% and 11%, respectively. We found that compared with a score of 10, newborns with a 5-minute-Apgar-score of 7-9 had increased risk of developing asthma (hazard ratio (95%CI): 1.13 (1.09-1.16) p<0.001) and eczema (1.20 (1.09-1.32) p<0.001), but not allergic rhinitis. Finally, the risk was similar among boys and girls in sex-stratified analysis.

Conclusions:
Lower Apgar-scores within the normal range increases the overall risk of asthma and eczema before school-age.