Additional file 2: of Exposure to air pollution during preconceptional and prenatal periods and risk of hypertensive disorders of pregnancy: a retrospective cohort study in Seoul, Korea ChoeSeung-Ah JunYoon-Bae KimSun-Young 2018 Figure S2. Odds ratios and 95% confidence intervals of three types of hypertensive disorders of pregnancy for interquartile range increases in five air pollutant concentrations for 12 months and 1 month before birth using different degrees of freedom in adjustment for a temporal trend. Patterns of risk estimates using different degrees of freedom were generally consistent with those of primary analyses. (DOCX 127 kb)