Curves are obtained at the mean and mode values for the following
continuous and categorical covariates, respectively : age at first birth (27
years), age in 1989 (35 years), race/ethnicity (white), parental education (12
years), physical activity at ages 18–22 (1–3 months/year),
pre-pregnancy smoking (never), pre-pregnancy body mass index (normal weight:
18.5–24.9 kg/m2), pre-pregnancy alcohol consumption (≤1
drink/week), pre-pregnancy Alternative Healthy Eating Index (AHEI) score
(3rd quintile), pre-pregnancy oral contraceptive use (≥4
years), family history of chronic hypertension (present; chronic hypertension
model only) and family history of type 2 diabetes mellitus (absent; type 2
diabetes mellitus model only). * P-value <0.001 from a global test of the
difference in the distribution of time to risk factor development between
hypertensive disorder in first pregnancy exposure groups. IQR = interquartile
range.