Many vitamin and mineral supplements promoted to pregnant women as a means of giving their child the best possible start in life, are an “unnecessary expense”, a review in Drug and Therapeutics Bulletin (dtb) has concluded.
Pregnant women would “do well to resist the marketing claims” and instead, focus on improving their overall diet and taking folic acid and vitamin D supplements, the report states.
“We found no evidence to recommend that all pregnant women should take prenatal multi-nutrient supplements beyond the nationally advised folic acid and vitamin D supplements, generic versions of which can be purchased relatively inexpensively,” the authors said.
“The marketing of such products does not appear to be supported by evidence of improvement in child or maternal outcomes.
“Pregnant women may be vulnerable to messages about giving their baby the best start in life, regardless of cost.”
In a bid to examine the evidence behind vitamin supplements recommended for pregnant women, the dtb reviewed the published research on folic acid, vitamin D, iron, vitamins C, E, and A, and multivitamin supplements.
The dtb states deficiency in key nutrients during pregnancy has been linked to various complications including pre-eclampsia, restricted foetal growth, neural tube defects, skeletal deformities and low birthweight.
A wide range of multivitamin and mineral supplements are heavily marketed to women for all stages of pregnancy to guard against these sorts of problems.
Typically these supplements contain 20+ vitamins and minerals, such as vitamins B1, B2, B3, B6, B12, C, D, E, K, folic acid, iodine, magnesium, iron, copper, zinc and selenium.
The dtb found that there was strong evidence to support national UK guidance on folic acid, which recommends that women take 400 ug of folic acid daily from before pregnancy, until they reach the 12 weeks mark.
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 ug is recommended throughout pregnancy and breastfeeding.
As for other supplements, there was “no evidence of any obvious clinical benefit for most women who are well nourished” and researchers found high doses of vitamin A may even harm the developing foetus.
The available data was not found to support the use of multivitamin supplements in most pregnant women either.
The dtb stated much of the evidence on which 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 than women in the UK.
“For most women who are planning to become pregnant or who are pregnant, complex multivitamin and mineral preparations promoted for use during pregnancy are unlikely to be needed and are an unnecessary expense,” the report concluded.
Commenting on the findings, Janet Fyle professional policy at the Royal College of Midwives (RCM) said: “This adds to a growing body of evidence that the benefits of eating a well-balanced nutritious diet during pregnancy cannot be underestimated in improving outcomes for both mother and baby.
“We would encourage women who are pregnant or are thinking of becoming pregnant to have a healthy, varied diet including fresh fruit and vegetables, alongside taking folic acid supplements.
“We would also stress that there is no need for pregnant women to ‘eat for two’. This is a myth and all that is required is a normal, balanced amount of food.
“In terms of vitamin D supplementation the benefits have been know for some time and currently UK Health Departments recommend that all pregnant and breastfeeding women should take a daily supplement containing 10µg of vitamin D, to ensure the mother’s requirements for vitamin D are met and to build adequate fetal stores for early infancy.”
Fyle said we need a “rethink of policy priorities” to ensure that all childbearing women can access folic acid supplementation at the right time.
“This is particularly important for women before conception where we need to ensure that women get better care, advice and support,” she added.
