Association between total dose of ritodrine hydrochloride and pulmonary edema in twin pregnancy: a retrospective cohort study in Japan

Objective Pulmonary edema is recognized as a severe side effect of ritodrine hydrochloride. Recently, the number of twin pregnancies has been increasing. Few studies have reported the association between total dose of ritodrine hydrochloride prior to delivery and pulmonary edema in twin pregnancy. We aimed to examine this association and determine the optimal cutoff threshold of total ritodrine hydrochloride dose to predict the incidence of pulmonary edema in twin pregnancy, based on obstetric records. Design Retrospective cohort study. Setting Yamanashi Prefectural Central Hospital, Japan Participants Two hundred twenty-six women with twin pregnancy who delivered at Yamanashi Prefectural Central Hospital between September 2009 and November 2016 Methods The obstetric records of the participants were analyzed. We defined one unit of ritodrine hydrochloride as 72 mg per 24 h continuous transfusion at 50 µg/min to calculate the dose of ritodrine used for tocolysis. Outcome measur...