Long-term intravenous tocolytic therapy

Eighteen women required continuous intravenous tocolytic therapy with either ritodrine hydrochloride or magnesium sulfate for greater than 48 hours because of repetitively recurrent preterm labor; these were compared with a similar group of women successfully treated in less than 48 hours in a retrospective, case-controlled study. The mean gestational age at the time of diagnosis was 31 weeks for both groups. Tocolytic selection was similar in both groups, although the dosage per hour was significantly greater with long-term therapy. The mean interval from initiation of therapy until delivery was 41 days in the study group, compared with 39 days among controls (not statistically significant). The mean gestational age at delivery was 36 weeks in both groups. There were no significant differences in various measures of fetal outcome between groups. These data demonstrate that long-term intravenous tocolytic therapy can be a safe and effective means of prolonging gestation in those women who fail to respond to conventional treatment.