Effectiveness of Nifedipine and Transdermal Nitroglycerin in Treatment of Preterm Labor

Background: Preterm labor (PTL) is one of the most serious complications of pregnancy and major cause of mortality in neonates. The present study aimed to compare the effectiveness of nifedipine and transdermal nitroglycerin in the treatment of PTL.

Materials and Methods: This randomized clinical trial was carried out on a total of women with PTL referring to Imam Reza Hospital of Mashhad University of Medical Sciences, Iran, during September 2016 to October 2017. The study participants were randomly divided into groups I and II with the administration of nifedipine and transdermal nitroglycerin. All the vital signs, fetal heart rates, contractions, dilation, and effacement, and Gestational Age (GA) at the time of delivery were monitored and evaluated in both groups. The main goal of this study was the postponement of delivery to secure the most beneficial effect of primary corticosteroid administration on the fetus.

Results: This study was conducted on a total of 112 women with a mean age of 27.12±3.37 years. There was a significant association between the average of GA in two groups (P=0.012), indicating group I with lower mean GA than that reported for group II at delivery. The difference regarding the average of labor suppression was statistically significant between the two groups (P=0.002). The obtained results of this study showed the neonates in the transdermal nitroglycerin group with higher Apgar scores of the first and fifth minutes than those in the nifedipine group. Moreover, the number of side effects of the transdermal nitroglycerin group (i.e., tachycardia and nausea) was higher than those reported for the nifedipine group (P=0.019).

Conclusion: The obtained results of this study demonstrated that the administration of transdermal nitroglycerin was more effective than that of nifedipine to stop the uterine contractions and consequently could slow the progression of delivery more efficiently. Furthermore, both medications were reported with some side effects for mothers; however, the number of the side effects of nifedipine was lower than that reported for transdermal nitroglycerin.