Women who take folic acid supplements early in their pregnancy can substantially reduce their infants’ chances of being born with a facial cleft, according to a study published online in the British Medical Journal.
Researchers at the National Institute of Environmental Health Sciences (NIEHS) found that 0.4 milligrams a day of folic acid reduced by one-third the infant’s risk of developing isolated cleft lip (with or without cleft palate). The recommended daily dietary allowance for folate for adults is 400 micrograms, or 0.4 mg.
"These findings provide further evidence of the benefits of folic acid for women," said Allen J. Wilcox, MD, PhD, lead author of the study.
"We already know that folic acid reduces the risk of neural tube defects, including spina bifida. Our research suggests that folic acid also helps prevent facial clefts, another common birth defect."
The researchers examined the association between facial clefts and mothers’ intake of folic acid supplements, multivitamins and folates in diet. They found that folic acid supplementation of 400 µg or more per day reduced the risk of developing isolated cleft lip, with or without cleft palate, by one-third, but had no apparent effect on the risk of developing cleft palate alone.
"A mother’s nutrition during pregnancy is clearly an environmental factor that can affect the health of her fetus," said NIEHS director David A. Schwartz, MD. The researchers are continuing to analyze their data for evidence of other environmental exposures that increase the risk of developing facial clefts.
This population-based study was conducted in Norway, which has one of the highest rates of facial clefts in Europe and does not allow foods to be fortified with folic acid.
The investigators contacted all families of newborns with clefts (either cleft lip with or without cleft palate [CLP] or cleft palate only [CPO]) born between 1996 and 2001 in Norway. The study included 377 infants with CLP and 196 with CLO, as well as 763 control infants selected randomly from all live births in Norway.
The researchers mailed two questionnaires to the participating mothers. The first questionnaire, mailed soon after delivery, focused on general health information, including demographics, reproductive history and information about environmental exposures such as smoking and use of alcohol and vitamins.
The second questionnaire focused on nutrition and diet (including consumption of fruits and vegetables) during the pregnancy. Mothers who reported taking folic acid supplements and/or multivitamins were asked to send in their empty bottles or labels to confirm dosage.
The researchers estimated that 22 percent of isolated CLP cases in Norway could be averted if all pregnant women took 0.4 mg of folic acid per day.
This study was supported by the NIEHS, National Institutes of Health, as well as by the Johan Throne Holst Foundation for Nutrition Research and the Thematic Area of Perinatal Nutrition, Medical Faculty of the University of Oslo, Norway.
