Study population and blood collection
Two independent cohorts of pregnant women were assembled for this study.
The testing cohort included sera from women between 25 and 31 wks’ of
gestation with or without PE collected by ProMedDX Inc. (Norton, MA).
Each woman had one sample collected. All PE samples were collected at
the time of confirmative diagnosis. The validation cohort included sera
from women who participated in a longitudinal study sponsored by the
March of Dimes Prematurity Center at Stanford University between
November 2012 and May 2016. Each woman had multiple sera collected from
5 to 29 wks’ of gestation prior to PE diagnosis. Study was approved by
ethics committees at Stanford University with an IRB#21956 starting
from Sep. 30th, 2011. Written informed consent was
obtained from all participants.
The diagnosis of PE was made according to the American College of
Obstetricians and Gynecologists criteria as follows: a persistent
systolic blood pressure ≥140 mmHg, or a diastolic blood pressure ≥ 90
mmHg after 20 wks’ of gestation in a woman having a previous normal
blood pressure in conjunction with one or more of the following:
new-onset proteinuria, new-onset thrombocytopenia, impaired liver
function, renal insufficiency, pulmonary edema, or visual or cerebral
disturbances in the absence of proteinuria. Early-onset PE was defined
as PE that develops before 34 wks’ of gestation, whereas the late-onset
PE develops at or after 34 wks’ of gestation.