Maternal pulmonary edema after 46 h of ritodrine hydrochloride administration: A case report

INTRODUCTION: Ritodrine hydrochloride is still widely used as a tocolytic agent in Japan, but it can cause maternal pulmonary edema, which may paradoxically induce preterm birth. Here we present a case of severe pulmonary edema due to <48 h of ritodrine administration. CASE: A 46-year-old woman was diagnosed with threatened preterm labor (TPL) and placenta previa at 26 weeks of gestation. She had mild uterine contractions and genital bleeding. Ritodrine hydrochloride, magnesium sulfate, and betamethasone were administered. She developed dyspnea 46 h after starting ritodrine administration. Chest X-ray showed pulmonary edema. Even after cessation of ritodrine, dyspnea did not lessen and there were regular uterine contractions with abdominal pain. Emergency caesarean section was performed. A female neonate was delivered and admitted to the neonatal intensive care unit. After surgery, maternal dyspnea decreased without any complications. DISCUSSION: Excessive use of ritodrine or its use in combination with other tocolytic agents can cause maternal pulmonary edema, even with <48 h of use. Adverse maternal side-effects and rebound uterine contractions due to cessation of ritodrine may paradoxically trigger preterm birth. Strict patient selection for tocolytic therapy is essential and ritodrine requires caution because of its potential side-effects.