Figure 3.

Simplified directed acyclic graphs to illustrate the potential causal structure of C-reactive protein, body mass index, and pregnancy. Figure 3A: Body mass index is a common cause of C-reactive protein and pregnancy, and therefore can be considered a confounder of the relationship between inflammation and fecundability. Figure 3B: Body mass index is an intermediate on the causal path from C-reactive protein to pregnancy, and therefore adjustment for adiposity would partially obscure the total effect of inflammation on fecundability.