Children born to women who take folic acid in late pregnancy are at increased risk for asthma, Australian researchers say.
The University of Adelaide study included more than 500 women whose diet and supplement intake were assessed during pregnancy. The women's children were checked for asthma at age 35 years and at 55 years. Asthma was found in 11.6% of children at 35 years and in 11.8% of children at 5.5 years.
"In our study, supplemental folic acid in late pregnancy was associated with an increased risk of asthma in children, but there was no evidence to suggest any adverse effects if supplements were taken in early pregnancy," said Michael Davies, MD, an associate professor at the university's Robinson Institute. The researchers also said they found no association between asthma and dietary folate, which is found in green, leafy vegetables, certain fruits and nuts.
Folic Acid Recommendations
Pregnant women are advised to take a supplemental dose of 400 micrograms (mcg) of folic acid per day in the month before and during the first trimester of pregnancy to reduce the risk of neural tube birth defects.
"Our study supports these guidelines, as we found no increased risk of asthma if folic acid supplements were taken in pre-or early pregnancy," Dr. Davies said. "However, these guidelines may need to be expanded to include recommendations about avoiding use of high-dose supplemental folic acid in late pregnancy."
The study was published in the American Journal of Epidemiology.
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