Testing multivitamins during pregnancy

Clinical trial 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 percent had low levels of vitamin D in their blood, 13 percent were anaemic and 12 percent 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. To the best of our knowledge, this is the first reporting of clinical findings in a study performed in either the UK or developed world showing 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 percent of women taking the placebo were anaemic compared to only 36 percent 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.

Of the 12 percent who were thiamin deficient at recruitment, by 34 weeks of gestation this increased to 32 percent in the placebo group compared to only 20 percent 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 percent, and in 2005 it was 8 percent (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.”

First study of it's kind

This study is the first double blind, randomised and controlled trial of multiple-micronutrient supplementation from the first trimester of pregnancy in a socially deprived, multiethnic population within a developed country.

The doctors

L Brough, GA Rees, MA Crawford, RH Morton, EK Dorman (2010) Effect of multiple-micronutrient supplementation on maternal nutrient status, infant birth weight and gestational age at birth in a low-income, multi-ethnic population. Dr Brough is currently a Lecturer in Human Nutrition based at Massey University, New Zealand.

Dr Gail Rees is currently based at the School of Biological Sciences at the University of Plymouth.

The study

This study was supported with funding provided by the Mother and Child Foundation. The multiple-micronutrient supplement and placebo tablets were manufactured and provided by Vitabiotics, London, UK. The supplement manufacturer had no influence or involvement in the study design, recruitment, conduct of the research, data analysis, writing or publication of the paper.

1 39 percent of participants remained compliant for the duration of the study. There was no statistical difference in the dropout rate in either group or tolerance / side effects associated with active or placebo interaction.

Source: British Journal of Nutrition

(Kelly Burke, Flux Communications, May 2010)