Table 2. Women who would benefit from 800 µg/d supplemental folate compared with 400 µg/d.

A starting RBC-folate that is close or below the population mean (i.e., ≤550 nmol/L)

Short time to pregnancy (<2 months)

Poor compliance with supplements or unwillingness to take supplements before conception

Women with MTHFR677 TT genotype

Disadvantaged women (i.e., low education, immigrants, low income)

Women with unplanned pregnancies

Women who start supplementation after a positive pregnancy screening test

RBC, red blood cell.