Is long-term tocolysis effective for threatened premature labour?

There is some controversy regarding the optimum duration of tocolysis. This retrospective multicentre study was performed to evaluate whether long-term (> 2 days) tocolysis is effective in treating threatened premature labour. A total of 1147 eligible patients were grouped according to whether or not tocolytics were given, and according to route of administration and whether or not ritodrine (the standard tocolytic regimen in Japan) or other tocolytic was given. They were then further stratified into three subgroups, using the Baumgarten and Gruber tocolysis index (TI), to assess the efficacy of tocolysis treatment according to the risk of premature labour. Prolongation of gestation was significantly longer in patients treated with tocolytics for > 2 days compared with the unmedicated, bed-rest group. In women receiving tocolysis, the mean duration of prolonged gestation was 2.2 times longer in the intermediate-risk TI group and 3.1 times longer in the high-risk TI group compared with the unmedicated group. In the patients who received tocolysis, IV ritodrine was used in 86% of cases and was considered safe and effective for prolonging gestation in cases of threatened premature labour.