Early Pregnancy Blood Pressure Trajectory Groups Predict Hypertensive Disorders of Pregnancy

Hypertensive disorders of pregnancy (HDP) cause significant maternal and fetal morbidity, but clinical tools to identify high-risk patients are lacking. Blood pressure (BP) trajectories in early pregnancy have predicted HDP.

In this study, we aimed to test these early BP trajectories in a distinct health system.

Electronic health record data were used to retrospectively identify patients with a singleton delivery from 2012 to 2020 in a large urban academic center. Patients with pre-existing hypertension or serious medical conditions were excluded. Each patient was assigned 1 of 6 previously identified BP trajectory groups from conception through 20 weeks' gestation. The primary outcome of HDP diagnosis, including preeclampsia and gestational hypertension, was identified using International Statistical Classification of Diseases codes. Multivariable logistic regression was used to model the relationship between patient factors and HDP diagnosis, and predictive model discrimination was assessed using C-statistics.

Among 25,879 patients, 5,694 (21.9%) were diagnosed with HDP. After adjustment for age, race/ethnicity, BMI, parity, and pregestational diabetes, BP trajectory groups were independently associated with increasing odds of HDP, with adjusted odds of HDP diagnosis progressively increasing from 1.6 (95% CI: 1.4-1.8) to 6 (95% CI: 5.3-6.9) across trajectories. Inclusion of trajectories into predictive models improved discrimination compared to clinical risk factors alone (C-statistic 0.71 [95% CI: 0.70-0.72] vs 0.66 [95% CI: 0.65-0.67]).

BP trajectories, based on early pregnancy BP measurements, improved ability to predict HDP diagnosis in diverse pregnant cohorts. BP trajectories may improve identification of high-risk patients for more intensive BP monitoring during pregnancy.