The advised dose is 0.4 to 0.8mg, unless you have been here before
Everyone who could become pregnant is advised 0.4 to 0.8mg of folic acid daily. Anyone whose earlier pregnancy was affected by a neural tube defect is moved to a high dose instead.
What the study found
One previous affected pregnancy moves you to a different dose
Everyone who could become pregnant is advised 0.4 to 0.8mg of folic acid daily, from before conception through pregnancy and breastfeeding. Anyone whose earlier pregnancy was affected by a neural tube defect is moved to a high dose instead. Roughly 3000 US pregnancies a year are affected.
The caveat · High dose never given in milligrams
The high-dose figure is deliberately absent here. The Canadian guideline states its tiers qualitatively rather than in milligrams, so no number can honestly be quoted from it, and an old trial dose is not a current recommendation. Both documents are graded syntheses of other people's work, resting partly on expert opinion where trials do not exist, and both address populations whose flour has been fortified since the 1990s.