Amendment October 2014: replacement of two-phase case-control study by two sub-projects, running in parallel, and following two distinct groups of women, 1) a cohort of 1500 non-pregnant women, disregarding Hb level, of whom 270 followed throughout pregnancy disregarding Hb level and gestational age at first contact, and 2) a case control study of 480 pregnant women followed from 1st trimester with a 160:160:160 ratio of women with Hb≤8g/dL: 8.1-10.9g/dL: ≥11g/dL.