Vitamin C

A few studies have shown that vitamin C deficiency plays a role in some pregnancy complications, such as premature rupture of membranes (PRM) and pre-eclampsia (Casanueva et al. 1991). Recent evidences from two, randomised, double-blind, placebo-controlled trials show how vitamin C (and other natural antioxidants) could be effective in decreasing the oxidative stress and thereby improving the course of pre-eclampsia (Gülmezoglu et al . 1997). The proportion preterm deliveries was higher in the placebo group (22/29) than in the antioxidant group (14/27), yielding a relative risk of 0.68 (0.45-1.04). Better results were achieved by Chappell and co-workers (Chappell et al . 1999): in the cohort who completed the study (81 placebo and 79 vitamin group) they found that the odds ratio for pre-eclampsia was 0.24 (0.08-0.70).These findings support the hypothesis that oxidative stress is responsible for the characteristic endothelial dysfunction of pre-eclampsia, as has been described by Roberts et al. (Roberts & Redman 1993, Roberts & Hubel 1999). A multicentre trial with large numbers of patients is needed, however, before introducing ascorbic acid in the clinical management of either pre-eclampsia or PRM as routine.