Pregnancy was reported to be a risk factor for coronavirus disease 2019 (COVID-19), with an increased risk for premature birth. Corticosteroids and remdesivir are used for patients with COVID-19; however, there is no established treatment for these patients. In particular, the effective management of pregnant, critically ill patients with COVID-19 remains unknown. We describe a 34-year-old, critically ill woman at 30 weeks of gestation with COVID-19, who was successfully treated with remdesivir and combined high-dose betamethasone (12 mg/day for two days) and methylprednisolone (125 mg/day for three days) followed by steroid tapering. During treatment, fetal biophysical profile scores on obstetric ultrasound were normal; her pregnancy course progressed well. Since high-dose corticosteroids improve fetal lung maturation and as well as cytokine storm due to COVID-19, this case provides an insight into the management of pregnant COVID-19 patients.