DOUBLE-BLIND EVALUATION OF RITODRINE SUSTAINED-RELEASE FOR ORAL-MAINTENANCE OF TOCOLYSIS AFTER ACTIVE PRETERM LABOR

Objective To evaluate the effect of ritodrine sustained release capsul es for maintaining uterine quiescence after successful treatment of ac tive preterm labour. Design Multicentre placebo-controlled trial. Sett ing Five teaching hospitals in the Netherlands. Participants Women (n = 95) at less than 35 weeks of gestation in whom active preterm labour had been stopped with intravenous ritodrine. Interventions Women rece ived either two 40 mg ritodrine sustained release capsules (n = 50) or identical placebo capsules (n = 45) three times a day for seven days. Results The proportion of women who received another course of active treatment was significantly smaller with the sustained release than w ith placebo (1 of 50 versus 11 of 45: P = 0.003) as was the number del ivering because of preterm labour during treatment (0 of 50 versus 4 o f 45: P = 0.04). There were no other significant differences between t he two groups. Conclusions Maintenance treatment with ritodrine sustai ned release capsules after arrest of preterm labour reduces the risk o f recurrences of preterm labour that necessitate treatment or precipit ate delivery.