A 28-year-old woman, G1P0 at 29 weeks’ gestation, was treated with terbutaline for preterm labor. Her cervix had dilated to 3 cm and was 90% effaced. She also received betamethasone intramuscularly to enhance fetal lung maturity.

The following day, the patient developed dyspnea, tachypnea, and an oxygen saturation level of 80% for which oxygen therapy was started.