Earlier start of micronutrient supplementation better for pregnant women and the unborn child

When pregnant women take supplements with micronutrients (vitamins and minerals), the growth of their unborn child improves. The improvement is cumulative, so researchers from the Antwerp Institute of Tropical Medicine report : the earlier in pregnancy the supplementation starts, the better. In developing countries, where women often have a poor diet, these supplements really make a difference. They publish in the Journal of Nutrition, the high-ranked journal of the American Society for Nutrition.

 Micronutrients are nutrients that are indispensable, even if we only need them in small quantities; among them are for instance folic acid and other vitamins, and trace elements like iron, copper, iodine, selenium, zinc. For pregnant women in industrialised countries micronutrients pose no real problem - they normally have a sufficiently rich and varied diet and most of them take supplements on top. The folic acid in those supplements helps in preventing spina bifida, but in our countries the other micronutrients mostly are a nice extra that is not really essential.  But in countries with low and middle incomes, the diet of pregnant women is often of low quality. This frequently results in growth retardation of the fetus in the womb, an important risk factor for ill health during later life.

Dominique Roberfroid and colleagues gave 1500 pregnant women in two health centers in Burkina Faso either daily supplements of 15 micronutrients, or the usual WHO-recommended supplements with only iron and folic acid. The tablets looked identical, to exclude the effects of prejudice or hope (the so-called placebo effect). The babies in the group with multiple micronutrients on average were heavier.

The scientists discovered that the effect of the micronutrients was cumulative: the longer the cure (or more precisely: the more tablets taken), the heavier and larger the baby. The odds for a small-for-gestational-age baby were reduced by 40% in mothers who had taken the most tablets in comparison to mothers whose tablet intake was in the lowest third.

A striking finding was that such cumulative effect was also observed in the group receiving only iron + folic acid. Up to now people thought the iron was mainly important to the mother. Mothers with a higher school education also delivered heavier babies, but this was mainly because they enrolled earlier in the study, and thus received more supplements.

However, there were no positive effects in pregnant women who were meager. This might be because mothers that do not get enough energy cannot fully utilize the micronutrients they receive, as the digestion and the transport of the nutrients to the fetus require energy - energy that isn't available.

Because of the cumulative effect, the researchers recommend to start the supplements of prenatal micronutrients as early as possible during pregnancy - or even before conception - and to stimulate the women not to skip their tablets. Pregnant women who are meager should be given extra food in addition to the micronutrient supplements.