title: Folic acid supplements in pregnancy and birth outcome: re-analysis of a large randomised controlled trial and update of Cochrane review.
abstract: Periconceptual folic acid prevents neural tube defects. The effect of folic acid taken throughout pregnancy is unclear, however. We re-analysed data from a large randomised controlled trial performed between 1966 and 1967 and combined the results with those from trials included in a Cochrane review. A total of 2928 women were randomised: 1977 were allocated to placebo, 466 to folic acid 200 microg/day and 485 to folic acid 5 mg/day. Folic acid supplementation was not associated with any difference in mean birthweight, placental weight or gestational age. When combined with trials in the Cochrane review folic acid at high doses was associated with reduced risk of low birthweight (pooled relative risk 0.73 [95% CI 0.53, 0.99]). We found no conclusive evidence of benefit for folic acid supplementation in pregnant women given from time of booking onwards.
authors.affiliation: Dugald Baird Centre For Research on Women's Health, Department of Obstetrics and Gynaecology, Aberdeen Maternity Hospital, Aberdeen, UK. d.charles@abdn.ac.uk
authors.forename: Deborah H M
authors.initials: DH
authors.lastname: Charles
authors.forename: Andy R
authors.initials: AR
authors.lastname: Ness
authors.forename: Doris
authors.initials: D
authors.lastname: Campbell
authors.forename: George Davey
authors.initials: GD
authors.lastname: Smith
authors.forename: Elise
authors.initials: E
authors.lastname: Whitley
authors.forename: Marion H
authors.initials: MH
authors.lastname: Hall
mesh_terms: D000328:Adult; D001724:Birth Weight / Q000187:drug effects; D019587:Dietary Supplements; D005260:Female; D005333:Fetus / Q000002:abnormalities; D005492:Folic Acid / Q000008:administration & dosage* / Q000097:blood; D005865:Gestational Age; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D009929:Organ Size / Q000187:drug effects; D010920:Placenta / Q000187:drug effects; D011225:Pre-Eclampsia / Q000139:chemically induced; D011247:Pregnancy; D011248:Pregnancy Complications / Q000139:chemically induced; D011256:Pregnancy Outcome; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors
chemical_list: D005492:Folic Acid