OBJECTIVE: To compare pulmonary function tests (PFTs), specifically passive respiratory system compliance (Crs), in infants of mothers positive for COVID-19 during pregnancy compared to PFTs from a historical cohort of matched, healthy reference infants. STUDY DESIGN: A prospective cohort study of infants born to COVID-19 positive mothers. Crs was measured with the single breath occlusion technique. Historical cohort data was obtained from a pre-COVID-19 data repository. Respiratory questionnaires were done at 1-year postnatal age. RESULTS: Twenty-four PFTs in the COVID-19 cohort were compared with PFTs from 24 reference subjects. Infants of the COVID-19 positive mothers had a Crs of 3.57 ml/cmH2O versus 3.76 mL/cmH2O in the reference group (p >
0.05). The remaining PFT outcomes were comparable between groups. The COVID-19 infants reported more allergic symptoms and conditions through 1-year. CONCLUSION: We found no difference in Crs in infants of mothers with COVID-19 during pregnancy compared to a historical pre-COVID reference cohort.