Vitamins C And E For Prevention Of Preeclampsia In Women With Type 1 Diabetes (Dapit): A Randomized Placebo-Controlled Trial Editorial Comment

The hypothesis that oxidative stress plays a major role in the pathogenesis of preeclampsia has been the focus of considerable research in the last 2 decades. Evidence for such a role was provided in a small, randomized, placebo-controlled trial showing that supplementation with vitamins C and E was associated with more than a 50% reduction in the rate of preeclampsia among a population of women at high risk of developing the disorder. Subsequently, the results of several large trials investigating antioxidant treatment in both women at low and high risk of preeclampsia showed that vitamins C and E supplementation during pregnancy was not beneficial. Only 3 of these trials included subgroups of women with diabetes and these groups were small and poorly characterized. The rates of preeclampsia are 2 to 4 times higher in pregnant women with diabetes than in nondiabetic women. The possible benefits of antioxidants in pregnant women with diabetes at risk of preeclampsia are unknown.The Diabetes and Preeclampsia Intervention Trial was a multicenter, randomized, placebo-controlled study designed to investigate whether supplementation with vitamins C and E reduced the incidence of preeclampsia in women with type 1 diabetes. The study subjects were singleton pregnant women, aged 16 years or older, who had type 1 diabetes before pregnancy, and presented between 8 and 22 weeks of gestation at 25 antenatal metabolic clinics in the United Kingdom. Women were randomly assigned to receive 1000 mg vitamin C and 400 IU vitamin E (n = 379) or matched placebo (n = 383) daily from 8 and 22 weeks' gestation until delivery. The primary outcome measure was preeclampsia defined as gestational hypertension with proteinuria.There was no difference in the rates of preeclampsia between the vitamin (15%, 57/375) and placebo groups (19%, 70/374); the risk ratio was 0.81, with a 95% confidence interval of 0.59 to 1.12. No significant differences were noted between vitamin and placebo groups for any adverse clinical maternal or fetal outcome.These findings indicate that the daily supplementation with vitamins C and E from early to mid pregnancy does not reduce risk of preeclampsia, gestational hypertension, or low birth weight infants in women with type 1 diabetes.