Editors' ChoicePreeclampsia

What to Ingest When You’re Expecting

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Science Translational Medicine  28 Apr 2010:
Vol. 2, Issue 29, pp. 29ec68
DOI: 10.1126/scitranslmed.3001197

The benefits of daily multivitamin use during pregnancy are well recognized. But when it comes to antioxidant vitamins, are more better? Recently released results of a large clinical trial show that for the pregnancy-related condition preeclampsia in low-risk patients, the answer appears to be no.

Several smaller studies previously have evaluated the ability of vitamins with antioxidant properties to reduce the risk of preeclampsia, a condition defined by pregnancy-associated high blood pressure and protein in the urine. The current hypothesis for how preeclampsia manifests is that reduced placental perfusion incites oxidative stress, followed by increased blood pressure and dysfunction of the endothelial cells that line the blood vessels. Early clinical trials suggested that supplementation of the diets of pregnant women with high doses of the antioxidant vitamins C and E reduced the risk of preeclampsia, although later studies were unable to reproduce these findings. To resolve the question, scientists conducted one of the largest double-blind trials on the use of vitamins C and E to prevent preeclampsia. More than 10,000 women in the 9th to 16th week of a first pregnancy who were at low risk for preeclampsia were randomized to receive either a placebo or a combination of 1000 mg of vitamin C and 400 IU of vitamin E. Study participants continued their regimen throughout pregnancy and were evaluated periodically for the presence of severe pregnancy-associated hypertension or the development of hypertension associated with other selected clinical findings, such as fetal-growth restriction or elevated liver enzymes. At the conclusion of the study, researchers noted no significant differences between the placebo and vitamin-treated groups for either target outcome, although unexpectedly, study participants in the vitamin-treated group showed a slight increase in the occurrence of pregnancy-associated hypertension without other clinical findings. Recently released results from Roberts et al. concluded that the use of high-dose antioxidant vitamins in low-risk pregnant patients is unlikely to yield a reduction in rates of preeclampsia.

J. M. Roberts et al., Vitamins C and E to prevent complications of pregnancy-associated hypertension. N. Engl. J. Med. 362, 1282–1291 (2010). [Abstract]

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