Background: Preterm labor is one of the main causes of neonatal mortality and its treatment is still challenging.
Objective: The study aimed to compare the effectiveness of nifedipine (Nif) with and without sildenafil citrate (SC) for the treatment of preterm labor in pregnant women.
Materials And Methods: In this clinical trial study, 126 pregnant women referred to the Fatemieh hospital, Hamadan, Iran with a complaint of preterm labor were evaluated.