Fig. 1

Association between maternal serum C-reactive protein concentration and spontaneous preterm birth in the PALUFER study. Fit and P-values derived from a logistic regression of preterm birth incidence (proportion) against log(CRP mg/l). Stippled lines are 95% confidence interval. Rugs at top and bottom indicate where preterm birth (red) and non-preterm birth (green) deliveries lie. ANC1 and ANC2 are the scheduled study antenatal visits. The regression slopes are 0.11 (95% CI − 0.06:0.29) for ANC1 and 0.39 (0.11:0.67) for ANC2 per unit log(CRP)