Unilateral Pulmonary Edema Associated With Prolonged Lateral Decubitus Positioning During Tocolytic Therapy in Pregnancy: A Case Report

Peripartum pulmonary edema is rare but potentially life-threatening for both the mother and fetus. Unilateral pulmonary edema is particularly uncommon and can mimic pneumonia, delaying appropriate diagnosis because of atypical radiologic findings. A 28-year-old pregnant woman (G3P1) hospitalized for threatened preterm labor received ritodrine hydrochloride and magnesium sulfate. At gestational week 25, she suddenly developed chest pain, dyspnea, and hypoxemia. Chest X-ray revealed unilateral, left-sided pulmonary infiltrates. Cardiac evaluation showed no evidence of cardiogenic pulmonary edema, and infection was excluded, suggesting drug-induced pulmonary edema. Tocolytic agents were discontinued; however, respiratory failure necessitated emergency cesarean delivery. Postoperatively, pulmonary edema rapidly improved with intensive care. A detailed history revealed prolonged left lateral decubitus positioning before symptom onset. Drug-induced pulmonary edema combined with prolonged lateral positioning may predispose pregnant women to unilateral pulmonary edema. Awareness of positional effects during tocolytic therapy is important for early diagnosis.