BackgroundPreterm premature rupture of membranes (PPROM) is one of the most important complications of the pregnancy and cause perinatal morbidity and mortality. History of PPROM is a risk factor of recurrent PPROM. Vitamin C plays an important role in collagen metabolism and increases resistance maintenance of the chorioamniotic membranes.ObjectivesThe aim of this study is to evaluate the role of vitamin C supplementation in prevention of PPROM in women with a positive history of PPROM.Patients and MethodsThis clinical trial study was performed on 170 pregnant women with the history of PPROM, with singleton pregnancy and gestational age 14 weeks in Imam-Reza Hospital, Mashhad University of Medical Sciences during 2008 to 2010. They were randomly divided into two groups. The case patients received 100 mg vitamin C daily from 14th weeks of gestation. PPROM occurrence was compared between two groups as an indicator of the protective effect of vitamin C supplements.ResultsPPROM occurred in 44.7% of controls and 31.8% of cases (P < 0.05). PROM occurred in 34.1% of controls and 18.8% of cases (P < 0.05). Pregnancy was terminated at term gestation in 21.2% of controls and 49.4% of cases (P < 0.05). Rupture of membranes was significantly decreased in the case group.ConclusionsVitamin C supplementations after 14th weeks of gestation can prevent from PPROM in women with the history of PPROM.