FIGURE 1.

Maternal early‐pregnancy ferritin level and child intelligence quotient (panel A) and language ability (panel B) at the 6‐year‐follow‐up. Panel A. Child intelligence quotient (points). Panel B. Child language ability (SD units). In the age‐and‐sex‐adjusted model (squares), associations were adjusted for child sex and age at the time of assessment. In the adjusted model (circles), we added as covariates the following maternal factors: age at enrolment (years), pre‐pregnancy body‐mass‐index (kg/m²), prospectively self‐reported smoking (none/quit when pregnancy was known/continued) and alcohol consumption (none/quit when pregnancy was known/continued occasionally/continued weekly), education at enrolment (tertiary/lower), parity (primipara/multipara) and maternal intelligence quotient estimate (continuous). Maternal ferritin was standardised for gestational age at the time of venepuncture. CI, Confidence Interval; Effect estimate: difference in intelligence quotient points (panel A) or language ability SD units (panel B), among children exposed to high ferritin (ferritin standard deviation score >1), or low ferritin (ferritin standard deviation score <−1), compared to reference group with intermediate ferritin (ferritin standard deviation score between −1 and +1; n = 1517 and n = 1415 for intelligence quotient and language ability analyses, respectively); N, group size; SD, standard deviation