Birth Weight Increase Seen with Folic Acid Supplementation
Lee Swanson Research Update
A study from the Netherlands finds that supplements of folic acid taken by the mother before conception may increase the birth weight of the baby by more than 60 grams.
Beginning folic acid supplementation before becoming pregnant was also associated with a 57% reduction in the risk of low birth weight and a 60% reduction in the risk of a baby that was small for gestational age (SGA), according to findings published online in the British Journal of Nutrition. The results add credibility to recommendations of a daily dose of 400 mcg for women of childbearing age, starting before conception.
Currently, supplementation with folate and folic acid—the synthetic, bioavailable form of folate—is recommended for all women of child-bearing age, since most neural tube defects (NTDs), including spina bifida and anencephaly, occur within the first 22 to 28 days of pregnancy, when the mother-to-be is not yet aware she is even pregnant. Folic acid supplements after this time are too late to prevent neural tube defects and therefore fail to benefit women with unplanned pregnancies—more than half of all pregnancies in the U.S.
This connection between folate deficiency in early pregnancy and an increased risk of NTDs led to the 1998 introduction of public health measures in the U.S. and Canada, where all grain products are fortified with folic acid.
The Dutch researchers, led by Sarah Timmermans, analyzed data on 6,353 pregnancies and considered the effects of folic acid supplementation (400 to 500 mcg per day) before, during and after conception on the birth weight of infants.
The Generation R Study found that folic acid supplementation before conception was linked with heavier babies and heavier placentas (13 grams more), compared to the infants of women who did not take any folic acid supplements.
Benefits were recorded for women who started the folic acid supplements after having their pregnancy confirmed, with an association noted for a 39% reduction in the risk of low birth weight. Starting folic acid supplementation before becoming pregnant was associated with reductions of over 50% in the risks of low birth weight and small for gestational age (SGA).
"In conclusion, periconception folic acid supplementation is associated with increased fetal growth resulting in higher placental and birth weight and decreased risks of low birth weight and SGA," concluded Timmermans and her co-workers.
British Journal of Nutrition Published online ahead of print.