Vitamins C and E did not reduce risk for pregnancy-related hypertension

The addition of vitamin C and E supplementation during pregnancy did not reduce the rate of severe pregnancy-associated hypertension or other severe related outcomes, study results suggested.

U.S. researchers enrolled 10,154 women who were no more than 15 weeks pregnant. The primary study outcome was a composite of pregnancy-associated hypertension and adverse outcomes in the mother or the fetus. Adverse outcomes were defined as severe pregnancy-associated hypertension alone or severe or mild pregnancy-associated hypertension with elevated liver enzyme levels, thrombocytopenia, elevated serum creatinine levels, eclamptic seizure, medically indicated preterm birth, fetal-growth restriction or perinatal death.

Women were randomly assigned to a daily supplementation of 1,000 mg vitamin C and 400 IU of vitamin E (n=4,993) or placebo (n=4,976) between the 9th and 16th weeks of pregnancy. The researchers reported no significant differences between the study groups for any component of the primary study outcome. There was also no significant difference in the rate of preeclampsia between the vitamin and placebo groups (7.2% vs. 6.7%).

There was no therapy benefit for women with severe pregnancy-associated hypertension or mild preeclampsia with one of the components of the primary outcome (RR=1.07; 95% CI, 0.89-1.27). Following a post hoc subgroup analysis based on week of pregnancy at random assignment (<13 weeks vs. >13 weeks), the researchers found no differences between the groups (P=.054).

“Previous studies have shown a similar lack of efficacy among high-risk women and among women who were likely to have had a deficiency of vitamins C and E,” the researchers wrote. “The findings of these several studies provide no support for the use of vitamin C and E supplementation in pregnancy to reduce the risk of preeclampsia or its complications.”

Roberts JM. N Engl J Med. 2010;362:1282-1291.

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