The research showed that a lower dose of iron offers women the same protection against iron deficiency, but with a lower risk of side effects.
"Most prenatal vitamins offered high iron content because that reflected the best scientific evidence available at the time," said Dr Fay Weisberg, an assistant professor in the department of obstetrics and gynecology at the University of Toronto.
Wyeth is reducing the amount of iron in Materna from 60mg to 27 mg, in line with the results of recent data.
"This level is deemed to be sufficient for pregnancy requirements for almost all women," Weisenberg told NutraIngredientsUSA. "There are certain medical or individual situations where a physician might recommend an iron supplement in addition to the prenatal vitamin, but such a practice needs to be done under medical advice and supervision.
According to market research carried out by Wyeth Consumer Healthcare, about 90 percent of expectant mothers take a prenatal vitamin to meet their nutritional needs. Until now, these vitamins contained 30-60 mg of iron. But, the Canada Anemia Review Panel has agreed that 20 to 30 mg is sufficient during pregnancy.
An Australian study published in 2003 in the American Journal of Clinical Nutrition even suggested that lower levels of iron could be equally effective.
A randomized, placebo-controlled trial looked at the effect of 20 mg/day of iron on maternal iron deficiency in around 400 women. The study found that at delivery fewer women from the iron-supplemented group than from the placebo group were anemic (3 percent compared to 11 percent), and fewer women from the iron-supplemented group had iron deficiency (35 percent compared to 58 percent).
Iron requirements increase during pregnancy, particularly during the second and third trimesters, and not all women have sufficient iron stores to meet these requirements, making anemia a common problem. Iron deficiency anemia can contribute to fatigue, reduced resistance to infection, and pre-clampsia in the mother, while the infant risks a premature birth and low weight at birth.