Clinical trials shows that multivitamins during pregnancy improve nutritional status of mothers in the developed world and may reduce the risk of small-for-gestational-age babies.
The results of a randomised, double-blind, placebo controlled trial published today in the British Journal of Nutrition show that taking a multiple micronutrient supplement (Vitabiotics Pregnacare tablets) during pregnancy may improve the health of pregnant women and their babies.
The collaborative study of over 4001 newly pregnant women was carried out by the Institute of Brain Chemistry and Human Nutrition at London Metropolitan University and the Homerton University Hospital.
The study found significant levels of vitamin and mineral deficiency amongst the mothers in East London during early pregnancy, which was of concern to the researchers. At the commencement of the study, 72% had low levels of vitamin D in their blood, 13% were anaemic and 12% were thiamin deficient.
Women taking the multiple micronutrient supplements during the trial rather than the placebo benefited from:
Improvement in nutrient status relative to the placebo. Markers of iron, folate, thiamin and vitamin D status were all higher during the third trimester in the vitamin group.
A reduction in numbers of small-for-gestational-age (SGA) infants (low birth weight for time of birth) relative to the placebo.
This study is the first clinical trial on maternal nutrition performed in either the UK or developed world to demonstrate that supplementing with a specific multivitamin supplement may help reduce the number of SGA infants born.
Dr Louise Brough, the lead researcher commented, "This research highlights the concerning fact that a number of women even in the developed world, are lacking in important nutrients during pregnancy. It also demonstrates the benefit of taking a multiple micronutrient supplement such as Pregnacare from early pregnancy.
"It is especially important to have good nutrient levels during early pregnancy as this is a critical time for development of the foetus. Nutrient deficiencies are correctable and they may influence birth outcomes. Of course a good diet during pregnancy is important for a healthy pregnancy, but for those who do not have a good diet, multivitamin and mineral supplements will help to reduce the risk of deficiency."
Of particular note was the effect of the Pregnacare supplement on iron deficiency. The level of iron provided (20 mg per day) was much less than typically prescribed during pregnancy (up to 300mg per day) and yet there was still an improvement in iron levels.
As pregnancy progressed iron levels fell, however the decrease was less in those receiving the supplement. In late pregnancy 55% of women taking the placebo were anaemic compared to only 36% of women taking the supplement.
This suggests that even women with good initial iron status may benefit later in pregnancy from low level iron supplementation. It is well known that patients have better tolerance of low dose iron supplements as used in the study, rather than high dose iron supplements. High dose iron supplementation is known to cause mild gastric side effects such as heartburn, nausea, vomiting, constipation and diarrhoea.
Low birth weight babies
Of the 12% who were thiamin deficient at recruitment, by 34 weeks of gestation this increased to 32% in the placebo group compared to only 20% in the treatment group.
The women from East London were recruited from the first trimester of pregnancy. Nutrient status was measured at recruitment, 26 and 34 weeks gestation. The study showed that the multiple micronutrient supplements may improve infant health by reducing the number of infants born small for gestational age.
The incidence of low birth weight babies in the UK is worse than any Western European country, even worse than Cuba and on a par with Romania. When data was gathered for the whole country in 1973 it was 6.6%, and in 2005 it was 8% (Unicef data).
Dr Brough commented, "A baby’s health can be adversely affected if it is too small at birth, both in early and later life. Being small for gestational age implies intra-uterine growth restriction and a degree of poor foetal nutrition.
This study shows that supplementing with a specific multivitamin supplement may help to reduce this. Although the numbers are small, the data is statistically significant and consistent with what is known about maternal-foetal nutrition and justifies a larger study."
- (London Metropolitan University Research Institute, May 2010)