The study was prompted by an earlier report from Spain suggesting that folic acid supplementation may "select for" embryos with deleterious mutations in the so-called MTHFR gene, the research team explains.
"A pretty serious concern raised in relation to folic acid use in pregnancy is not something to worry about," Dr. Paul Haggarty from Rowett Research Institute, Aberdeen, UK told Reuters Health.
"Women should continue to follow advice on folic acid use to reduce the chances of the very serious condition of neural tube defects," he added.
Haggarty and colleagues analysed the MTHFR "genotypes" of mothers and their babies before and after recommendations of folic acid supplementation in pregnancy.
They could find no significant differences between mothers and babies in the frequencies of all five MTHFR mutations studied before and after the introduction of advice on folic acid supplementation.
"The original finding was such an interesting idea that it was widely cited in good quality journals without being challenged," Haggarty said. "There are subtle ways that folic acid could influence embryo development and long term health... but this is only speculation."
Haggarty concluded, "We know that there is a clear health benefit of folic acid use in terms of reducing neural tube defect risk and that should not be put in jeopardy until we have hard data that there is a health detriment."