Multivitamins lower risk of underweight newborns

Women who take multivitamin supplements during pregnancy have significantly lower risk of giving birth to an underweight infant, according to a study in the Thursday edition of the New England Journal of Medicine.

Tests carried out in Tanzania on 8,468 pregnant women who were not infected with the
AIDS virus "demonstrated that multivitamin supplements significantly reduced the risks of low birth weight and a birth size that was small-for-gestational age, by 18 percent and 23 percent, respectively," the researchers said in a statement published Wednesday.

Test participants enrolled at 12 to 27 weeks gestation. Half of the group took multivitamins -- vitamins C, E and a variety of vitamins B -- every day while the other half took a placebo until six weeks after delivery.

Vitamin A and zinc were not added into the vitamin cocktail because previous studies failed to show a beneficial effect of those nutrients.

Women from both groups also received iron and folate supplementation and malaria prophylaxis, which is standard prenatal care in Tanzania.

Birth weight is influenced by factors that include maternal health, nutritional status and micronutrient deficiencies, according to the study's authors.

"Each year an estimated 20 million children are born with low birth weight worldwide, more than 95 percent of them in developing countries," the statement read.

Low birth weight -- 2,500 grams (5.5 pounds) or less -- "is associated with increased risk of negative health outcomes, including neonatal and infant mortality, poor growth and cognitive development, and morbidity due to chronic diseases later in life, such as diabetes and heart disease."

The study, the largest to date on the subject, was conducted by researchers from the Harvard School of Public Health (HSPH) and Muhimbili University College of Health Sciences in Dar es Salaam.

Wafaie Fawzi, professor of nutrition and epidemiology at HSPH and the study's main investigator, said his team recommends "that multivitamins be considered for all pregnant women in developing countries, regardless of their
HIV status."