Effects of Ascorbic Acid on Serum Level of Unconjugated Estriol and Its Relationship with Preterm Premature Rupture of Membrane: A Double-Blind Randomized Controlled Clinical Trial

Background: Vitamin C is a water-soluble antioxidant that not only stimulates and protects collagen synthesis but also plays an important role in maintaining cellular integrity in a normal pregnancy. This study surveyed the effects of ascorbic acid on the serum level of unconjugated estriol and the relationship between unconjugated estriol and preterm premature rupture of membrane (PPROM). Methods: This double-blind, randomized clinical trial recruited 60 patients with predisposing factors to PPROM. The women were randomly divided into two groups of intervention and control and received vitamin C and placebo, respectively. The intervention group received 250 mg vitamin C twice a day and the controls received the placebo only. Unconjugated estriol was measured using the ELISA. All data were extracted and recorded in a checklist and compared using descriptive statistics as well as the x(2), Fisher exact, and t tests. Results: The demographic data showed no difference between the two groups. The mean level of serum unconjugated estriol was significantly lower in the intervention group than in the control group (P=0.044). Also, the frequency of PPROM was lower in the intervention group, but the difference was not significant (P>0.05). Unconjugated estriol levels were not significantly different between the healthy women and the PPROM patients. Conclusion: This study demonstrated that vitamin C administration decreased unconjugated estriol levels in the patients with PPROM. The findings of this study also indicated that administration of ascorbic acid was a safe and effective method to reduce the incidence of PPROM. Alteration in unconjugated estriol is an active mediator for this effect.