A Cochrane review [Abstract] 1 included 5 studies with a total of 766 subjects. No difference was seen between women supplemented with vitamin C alone or in combination with other supplements compared with placebo for the risk of stillbirth (relative risk (RR) 0.87, 95% confidence intervals (CI) 0.41 to 1.87, three trials, 539 women), perinatal death (RR 1.16, 95% CI 0.61 to 2.18, two trials, 238 women), birthweight (weighted mean difference (WMD) -139.00 g, 95% CI -517.68 to 239.68, one trial, 100 women) or intrauterine growth restriction (RR 0.72, 95% CI 0.49 to 1.04, two trials, 383 women). Women supplemented with vitamin C compared with placebo were at increased risk of giving birth preterm (RR 1.38, 95% CI 1.04 to 1.82, three trials, 583 women). Significant heterogeneity was found for neonatal death and pre-eclampsia. No difference was seen between women supplemented with vitamin C compared with placebo for the risk of neonatal death (RR 1.73, 95% CI 0.25 to 12.12, two trials, 221 women), using a random-effects model. For pre-eclampsia, women supplemented with vitamin C were at decreased risk when using a fixed-effect model (RR 0.47, 95% CI 0.30 to 0.75, four trials, 710 women), however this difference could not be demonstratedwhen using a random-effects model (RR 0.52, 95% CI 0.23 to 1.20, four trials, 710 women).
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