For a study, researchers sought to determine the safety and efficacy of propranolol for the treatment of infantile hemangiomas (IH) in infants aged less than five weeks or 45 weeks corrected gestational age (CGA). Between 2017 and 2021, investigators conducted a retrospective review of patients treated with propranolol for six months at a single institution. Patient characteristics, hemangioma(s) location, weight at treatment commencement, dose information, adverse effects, response, and therapy duration were all reported. About 24 patients with IH who received propranolol started treatment before the 45-week CGA. At the start of treatment, the average CGA was 42 weeks. About 67%  of the participants were female, and 75% were non-Hispanic white. The average treatment time was 255 days. Treatment at a dose of 1–3 mg/kg/day provided a clear benefit to 22 patients (92%). Sleep disturbance (21%), irritability (17%), and cold hands/feet were the most prevalent side effects (13%). There were no significant side effects. Propranolol was safe and effective for treating infantile hemangiomas in this group of 24 individuals with a corrected age of fewer than five weeks (CGA 45 weeks). Propranolol should be studied in this age group in larger prospective investigations.