Definitions of outcomes and risk factors
Diagnoses and the following definitions were in alignment with ICD-9 and ICD-10 codes [International Classification of Diseases, Ninth (1996) and Tenth (1997–2010) Revisions]. Preeclampsia was defined as the combination of gestational hypertension plus proteinuria (≥ 300 mg/24 h or > 2+ by dipstick on 2 or more occasions) occurring after 20 weeks of gestation.(15) The superimposed preeclampsia was defined as those who developed preeclampsia with concomitant chronic hypertension, based on the revised criteria of the International Society for the Study of Hypertension in Pregnancy (ISSHP) in 2018. (25) According to the revised recommendations for gestational hypertension diagnosis from the ACC/AHA Task Force,(15) normal blood pressure was defined as systolic blood pressure (SBP) < 120 mmHg or diastolic blood pressure (DBP) < 80 mmHg; elevated blood pressure as SBP between 120 and 129 mmHg or DBP < 80 mmHg; stage 1 hypertension as SBP between 130 and 139 mmHg or DBP measurement between 80 and 89 mmHg; stage 2 hypertension as SBP measurement > 140 mmHg or DBP measurement > 90 mmHg.
The main outcome measures in the analysis included early-pregnancy maternal TG concentrations and pre-pregnancy BMI. Other risk factors included maternal age, early-pregnancy BMI, education (years), birthplace (immigrant or resident), parity (1 or above 2), and ethnicity (Han Chinese or other) (Table 1 ).