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 ).