The effects of periconceptional and prenatal folic acid supplementation on congenital anomalies and preterm birth. (WC2009-013)


Starting date: 04/04/2012

Randomised controlled trials (RCTs) proved 20 years ago periconceptional use of folic acid (FA, vitamin B11) reduces the risk for neural tube defects (NTDs) considerably. Uncertainty about the optimal dose and duration of FA supplementation still remains. An RCT is needed to assess whether a higher dose and longer duration than currently recommended in the Netherlands have a higher protective effect on congenital anomalies and pregnancy complications respectively.
Between 200.000 and 300.000 cases of NTD are born each year worldwide. The other  FA-related congenital anomalies (heart anomalies, limb defects, urinary tract malformations, oral clefts and Down syndrome) that might be prevented with FA-supplementation outnumber the figures for NTD largely. In the Netherlands, these FA-related anomalies affect 1,35% of 180.000 pregnancies per year.
Another possible preventive effect of FA supplementation during pregnancy (2nd and 3rd trimester), is on the prevalence of preterm birth and preeclampsia. However this evidence comes from case-control and cohort studies and is not yet confirmed by an RCT.