Fig. 1
Odds ratios and 95% confidence intervals of three types of hypertensive disorders of pregnancy for interquartile range increases in five air pollutant concentrations by four exposure periods in 18,835 pregnant women residing in Seoul from the Korean National Health Insurance Service–National Sample Cohort for 2002–2013. PM10, particulate matter; NO2, nitrogen dioxide; CO, carbon monoxide, SO2, sulfur dioxide; O3, ozone; GHTN, Gestational hypertension; PE, preeclampsia; Mg-PE, preeclampsia requiring magnesium sulfate. Date of birth was adjusted using non-parametric cubic spline smoothing (degree of freedom = 12)