METHODS
Study design
Between 2019 and 2021, this research was performed at Qazvin’s Kosar Hospital(Kosar hospital which we chose patients was the only women’s specialty hospital in Qazvin state, which means that more than 12 hospitals in the state refer their patients with preterm labor to this center. As a result, patients can select from more than 12 centers). In this interventional study, which was conducted as a double-blind, randomized clinical trial, 200 women with preterm labor symptoms referred to this center were chosen and evaluated via convenience sampling. Patients were divided into two groups  randomly : A (n = 100) and B (n = 100).
Magnesium Sulfate was administered intravenously to group A first at a dose of 4-6 gr, then at a dose of 2 gr/h for 12 hours after the uterine contractions stopped, or for up to 48 hours. Furthermore, they were given a 100mgr rectal Indomethacin suppository every 12 hours until the uterine contractions stopped, or for a maximum of 48 hours. Group B received Magnesium Sulfate intravenously at a dose of 4-6 g, followed by 2 gr/h for 12 hours after the uterine contractions stopped or for a maximum of 48 hours. Group B received a placebo suppository, which was similar to the Indomethacin suppository. Then, the required information was entered into the checklist, and the data were entered into SPSS V24 statistical software and analyzed using the analytical, statistical method.
findings :
According to the findings of the study, the majority of patients were between the ages of 21 and 25. The mean age of the referring women was 27.12 + 5.43 years, and their BMI was 27.41+ 3.53. Also, maternal gravid was between 1 to 5, and the mean maternal gravid was 1.85+ 0.92, and 22 of them (11%) had a history of preterm delivery. There was no statistically significant difference between the two groups regarding baseline characteristics such as maternal age, gravidity, and history of preterm delivery. In addition, the maternal gravid was between 1 and 5, with a mean maternal gravid of 1.85+ 0.92, and 22 of them (11%) had a history of preterm delivery. In terms of baseline characteristics such as maternal age, gravidity, and history of preterm delivery, there was no statistically significant difference between the two groups. However, there was a statistically significant difference between the two groups in the two variables of BMI and gestational age at the time of admission, so the patients in the group who received Magnesium Sulfate alone had a higher BMI and higher gestational age at the time of admission compared to the group of patients who were receiving  Magnesium Sulfate and Indomethacin (P <0.05).
The mean time interval between receiving the drug and delivery in group A (Magnesium Sulfate + Indomethacin) was 774.71 + 505.91 and in group B (Magnesium Sulfate) was 545.77+ 503.32 hours.
According to the Whitney U-MANN test, the relationship between the type of intervention and the time interval between receiving the drug and delivery was statistically significant (P <0.05).
Also, 15% of the patients in the group receiving Magnesium Sulfate versus 8% of the patients in the group receiving Magnesium Sulfate and Indomethacin gave birth within 48 hours after starting the drug. According to the Chi-square test results, this difference was not statistically significant (P > 0.05). According to the test results, 31% of the patients in the group receiving Magnesium Sulfate versus 15% of the patients in the group receiving Magnesium Sulfate and Indomethacin had spontaneous delivery within seven days after receiving the tocolytic drug, which according to the test results, Chi-Square This difference was statistically significant (P <0.05).
Also, no significant differences were observed between the two groups in any of the secondary outcomes, according to the results of logistic regression and according to the data displayed in Table 1,among the variables of maternal age, gestational age at admission time, gravidity, BMI, and type of intervention. Only the variables of intervention type and gestational age at the time of Referrals could predict spontaneous delivery within seven days of starting the tocolytic drug.
After adjustment, the type of intervention was still significantly related to the rate of spontaneous delivery within 7 days of starting the tocolytic drug.( Figure-1) ( Exp (B)=2.08,P= 0.048).