PROJECT SUMMARY/ABSTRACT
Hypertensive disorders in pregnancy (HDP) are a leading cause of maternal morbidity, affecting over 350,000
pregnant U.S. women annually. HDP rates increased dramatically in the past decades. Clinical care and
management for this growing group of women is complicated, however, by conflicting guidelines, uncertain
evidence for postpartum care, and important comorbidities that may impact outcomes. In 2017, the American
College of Cardiology/American Heart Association (ACC/AHA) issued new guidelines to define chronic
hypertension by using lower systolic/diastolic blood pressure (SBP/DBP) thresholds (stage 1 hypertension,
130-139/80-89; stage 2, =140/90 mmHg) down from =140/90. In 2019, the American College of Obstetricians
and Gynecologists (ACOG) confirmed much of this recommendation but did not apply the lower BP thresholds
to diagnose new-onset HDP, due to the lack of data on the associations between these lower BP thresholds
with prenatal and postpartum complication. The ACOG also recognized it is not scientifically substantiated to
use the 20-week mark to determine whether hypertension predates pregnancy or is pregnancy-related, calling
for examination of BP trajectories across pregnancy. Further, due to fragmented postpartum care, little is
known about postpartum hypertensive disorders and associated hospitalization and severe maternal morbidity.
Finally, pre-existing obesity and diabetes often cluster with HDP and complicate the association between BP in
pregnancy and risk of complications. To address these critical knowledge gaps, we propose a population-
based cohort study of ~0.5 million demographically diverse women who delivered singletons in 2007-2019 at
Kaiser Permanente Northern California (KPNC), an integrated health care system with a stable membership
and comprehensive electronic medical record data. We are uniquely positioned to timely address the important
concern regarding the unknown association of the 2017 ACC/AHA defined BP categories in pregnancy with
perinatal and postpartum complications (Aims 1-2). Leveraging KPNC’s unique longitudinal tracking of BP and
weight before, during, and after pregnancy and robust diabetes diagnosis data before pregnancy, we will be
able to efficiently dissect the joint effects of BP in pregnancy with comorbid obesity and diabetes on perinatal
and postpartum complications (Aims 1-2). Finally, we will examine BP trajectories on a continuum before 20
weeks of gestation and across pregnancy with risk of complications (Aim 3). This study provides a timely and
unparalleled opportunity to address the concerns arising from the conflicts between the ACC/AHA and ACOG
guidelines regarding how to manage pregnant women with BP levels lower than conventional thresholds. Our
findings may help identify at which BP level, and in which time window, closer patient surveillance and change
in management may be initiated. Further, our findings may provide clinicians with sorely needed data to inform
early clinical triage and risk stratification of women with combinations of certain BP categories in pregnancy
and comorbid obesity and diabetes, thus enhancing individualized care decision and efficiency.