Pregnant women do not need to be taking expensive and unproven multivitamin and mineral supplements, a review published in the Drug and Therapeutics Bulletin has found.
Pregnant women would do well to resist the marketing claims, which don’t translate into better outcomes for mother or baby. Instead women would be better to focus on improving their overall diet and taking folic acid and vitamin D supplements, it says.
Much of the evidence on which the marketing claims for multivitamin supplements are based, comes from studies carried out in low income countries, where women are more likely to be undernourished or malnourished, the review said.
Good nourishment, both before and during pregnancy, is essential for the health of the mother and her unborn child and deficiency in key nutrients has been linked to complications including preeclampsia, restricted foetal growth, neural tube defects, skeletal deformities and low birthweight.
The Bulletin reviewed the published research on folic acid, vitamin D, iron, vitamins C, E, and A, and multivitamin supplements and found that folic acid had the strongest evidence to support supplement taking. UK guidance recommends women take 400 ug of folic acid daily from before, until 12 weeks of, pregnancy.
A daily dose of 5 mg is recommended for those women at higher risk of having a child with neural tube defects – those who have neural tube defects themselves, a family history of the condition, or who have diabetes.
The evidence for vitamin D supplementation was less clear-cut, with little of the trial data showing any impact on reducing the risk of complications of pregnancy or birth, the review found.
Nevertheless, a daily dose of 10 mg is recommended throughout pregnancy and breastfeeding.
For the other supplements there was no evidence of any clinical benefit for women who were well nourished, and high doses of vitamin A may in fact harm the developing foetus.