Folic acid before conception may boost birth weight: Study

Starting folic acid supplementation before falling pregnant was also associated with a 57 per cent reduction in the risk of low birth weight, and a 60 per cent reduction in the risk of a baby that was small for gestational age (SGA), according to findings published online ahead of print in the British Journal of Nutrition​.

The results add weight to recommendations of a daily dose of 400 micrograms for women of childbearing age, starting before conception.

Folic acid and NTDs​

Currently, supplementation with folate and folic acid - the synthetic, bioavailable form of folate - is recommended to 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 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 US.

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 US and Canada, where all grain products are fortified with folic acid.

While preliminary evidence indicates that the measure is having an effect with a reported 15 to 50 per cent reduction in NTD incidence, parallel measures in European countries, including the UK and Ireland, are still on the table.

Folic acid and birth weight​

The Dutch researchers, led by Sarah Timmermans from Erasmus MC, analysed data on 6,353 pregnancies and considered the effects of folic acid supplementation (400 to 500 micrograms per day) before, during, and after conception on the birth weight of the 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 per cent reduction in the risk of low birth weight.

Starting folic acid supplementation before falling pregnant was associated with reductions of over 50 per cent in the risks of low birth weight and small for gestational age (SGA).

“In conclusion, periconception folic acid supplementation is associated with increased foetal growth resulting in higher placental and birth weight, and decreased risks of low birth weight and SGA,”​ concluded Timmermans and her co-workers.

Source: British Journal of Nutrition​ Published online ahead of print 30 March 2009, doi:10.1017/S0007114509288994“Periconception folic acid supplementation, fetal growth and the risks of low birth weight and preterm birth: the Generation R Study”​ Authors: S. Timmermans, V.W.V. Jaddoe, A. Hofman, R.P.M. Steegers-Theunissen, E.A.P. Steegers