Women who were taking daily multivitamins in and around the time of conception gave birth to babies who weighed on average half a kilo more than babies from women not taking the supplements, report Heather Burris from Harvard University and Allen Mitchell and Martha Werler from Boston University in the Annals of Epidemiology.
“African American women in the United States deliver preterm and low birth weight infants two to three times more frequently than their white counterparts,” explained the Boston-based researchers.
Low birth weight has been linked to higher risks of negative health outcomes, including neonatal and infant mortality, poor growth and cognitive development, and higher risks of chronic diseases later in life, like diabetes and heart disease.
“If our findings were confirmed and subsequently shown to be causal, then increasing peri-conceptional multivitamin use among African American women in the United States could help to eliminate longstanding disparities in birth weight, gestational age, and foetal growth,” they added.
Burris and her co-workers analysed data from 2,331 non-Hispanic white and 133 non-Hispanic black mothers and their infnats participating in the Slone Epidemiology Center Birth Defects Study.
While no link was association between multivitamin use in white women and the birth weight or gestational age of their infants, a significant increase in birth weight was observed in babies from African American women. Indeed, multivitamin use in African Amercian women was associated with an increase in birth weight of their infants of about 540 grams. Furthermore, there was a trend toward increased gestation periods in these women, added the researchers.
Being an epidemioligical study, the resutls do not prove causality and the researchers note that it is possible that multivitamin use is merely indicative of a healthy lifestyle, which would produce healthier pregnancies.
Despite this limitation, Burris and her co-workers note that the findings are “consistent with a plausible role played by micronutrients in foetal growth.
“It is not known which nutrient or combination of nutrients in multivitamins might affect foetal growth, and our data do not contribute to this question,” they added.
Building the science
An earlier clinical study, also from Harvard and published in the New England Journal of Medicine in 2007 (Vol. 356, pp. 1423-1431), reported that Supplementation with multivitamins during pregnancy may boost the birth weight of newborns, and should be considered for all expectant mothers in developing countries.
Source: Annals of Epidemiology
March 2010, Volume 20, Issue 3, Pages 233-240
“Periconceptional Multivitamin Use and Infant Birth Weight Disparities”
Authors: H.H. Burris, A.A. Mitchell, M.M. Werler