Fig. 1: Directed acylic graph of assumed causal relationships.

The simplified directed acyclic graph displays the hypothetical causal relationships linking prenatal exposure (E), cord blood metabolites (M1), rapid postnatal growth (M2) and childhood overweight (Y). NDE: natural direct effect; NIE: natural indirect effect; NIEM1: natural indirect effect through M1; NIEM2: natural indirect effect through M2. For simplicity, confounders of the E-Y, E-M1, E-M2, M1-M2, M1-Y, M2-Y associations were not shown.