Tocolysis in women with advanced preterm labor: a secondary analysis of a randomized clinical trial.

Objective: To compare the efficacy of tocolytic treatment with indomethacin (I), magnesium sulfate (M) and nifedipine (N) for acute tocolysis in women with advanced cervical dilation (4-6 cm).

Methods: A single center, randomized trial was carried out involving patients in preterm labor (cervix 1-6 cm). Secondary analysis of women with advanced cervical dilation (cervix 4-6 cm) at 24-32 weeks' gestation who received intravenous M, oral N or I suppositories comprised this study population.

Results: Over 38 months, 92 women with advanced cervical dilation were randomized to one tocoloytic type. Days gained in utero (11.7) and percent remaining undelivered at 48 h (60.8%), 72 h (53.1%) and >7 days (38.3%) were similar regardless of tocolytic employed (p = 0.923, 0.968, 0.791, 0.802, respectively). Likewise, gestational age at delivery (30.7 ± 3.2) was similar between groups (p = 0.771). Finally, neonatal statistics were not different when stratified by tocolytic treatment.

Conclusion: There were no statistical differences between tocolytics in treating women with advanced cervical dilation. All offered significant days gained in utero after therapy, a high percentage remaining undelivered after 48 or 72 h and after 7 days. It would appear from data that there may be advantages to tocolytic treatment even in women with advanced cervical dilation.