Background: The prevalence of preterm labor in Iran is 6-10%, accounting for 80% of neonatal morbidity. The most effective tocolytic agents to delay the preterm labor have not yet been known. Therefore, this study aimed to compare the effects of Indomethacin (ICN) and Magnesium-Sulfate (Mg) in delaying preterm labor and also to assess the maternal complications associated with the two drugs.

Materials and Methods: This randomized clinical trial study was performed on 24-32 week pregnant women (n=60) at risk for preterm labor referred to Shabih-Khani maternity hospital in Kashan. The women were divided into two equal groups: intravenous Mg sulfate (control) or ICN rectal suppository (intervention) groups. Then, the delaying of preterm labor and also the maternal morbidity were assessed in both groups.

Results: No significant difference was seen in maternal and sociodemographic variables between the two groups. The delaying of preterm labor was the same for both groups and no case of preterm labor was seen in women during the first 48 hours of hospitalization. Moreover, there was no significant difference in variables (e.g. the maternal age, the number of gravida, gestational age, symptoms on admission, the number of prior preterm labors and a history of preterm labor) between the two groups. The most common complication in both groups was nausea. There was no case of oligohydramnios in the indomethacin group.

Conclusion: Although the delaying of preterm labor was the same in both groups, Mg sulfate administration requires permanent nursing care. It seems that ICN can be used as one of primary tocolytic treatments in preterm labor.