Fig. 5

Path model for evaluation of inflammatory factors influencing preterm birth and gestation. See Additional file 3. A fitted path model. Fitted coefficients are shown along the paths and represent effect sizes [differences in log(hepcidin), log(CRP), or gestation, or odds ratios for PTB per unit log(CRP), log(hepcidin)], treatment/non-treatment or amplitude of seasonal variability with 95% CI. The CRP–hepcidin relationship is non-linear and is illustrated graphically (see also Additional file 4: Figure S2). The model fits both PTB and gestation (in days), so there are coefficients for both relationships indicated by blue and green text respective