Mediating variables

Natural direct effect, risk ratio (95% CI)

Natural indirect effect, risk ratio (95% CI)

Proportion indirect


All women

Placental malaria only

0.47 (0.25, 0.83)

0.92 (0.63, 1.25)

7%

Anaemia and placental malaria

0.45 (0.25, 0.79)

0.88 (0.60, 1.18)

10%

Malaria, anaemia and placental malaria

0.44 (0.25, 0.79)

0.87 (0.69, 1.39)

12%

Sensitivity analyses*

Placental malaria only

0.34 (0.17, 0.79)

1.09 (0.67, 1.80)

4%

Anaemia and placental malaria

0.33 (0.17, 0.78)

1.07 (0.63, 1. 86)

4%

Malaria, anaemia and placental malaria

0.33 (0.17, 0.78)

1.06 (0. 65, 1.84)

3%

 Numbers are risk ratios (95% confidence interval). Natural direct effect is the effect of iron deficiency on birth outcome, not mediated through the specified mediators. Natural indirect effect is the effect of iron deficiency on birth outcome, mediated through the specified mediator.
 CI confidence interval
 *Women potentially misclassified as iron deficient (ferritin > 15 and Creactive protein > 10) are excluded from analysis (N = 46)