Abstract
Introduction
Preeclampsia is a leading cause of maternal morbidity and mortality worldwide. While screening guidelines exist to identify patients at increased risk of preeclampsia, those currently recommended by the United States Preventive Services Task Force (USPSTF) rely solely on maternal characteristics and are estimated to predict only 15% of eventual cases.
Objective
To determine an early pregnancy mean arterial pressure (MAP) cut-point for use in preeclampsia risk stratification and to compare the predictive characteristics of this cut-point with those of the maternal characteristics recommended by the USPSTF screening guidelines.
Study Design
Retrospective cohort study of pregnant persons with a first prenatal visit by 16 weeks’ gestation and delivered in our system from January 2021 to December 2022. MAP was calculated using data captured at the initial visit. Preeclampsia risk was assessed using the 2021 USPSTF risk screening algorithm in which a positive screening was defined as having 1 high or 2 or more moderate risk factors for the condition and a negative screening was defined as having none. Primary outcome was preeclampsia. Youden index was used to identify an optimal early pregnancy MAP cut-point for predicting preeclampsia. Predictive abilities of this cut-point and the USPSTF preeclampsia risk screening algorithm were compared using area under the receiver operating characteristic (AUROC) curves, sensitivity, specificity, and positive and negative predictive values.
Results
Of 2169 patients, 230 (11%) developed preeclampsia. The optimal MAP cut-point for predicting preeclampsia was 88.5 mm Hg. MAP outperformed the USPSTF preeclampsia risk screening algorithm with respect to predicting this diagnosis, as evidenced by AUROC of 0.71 compared to 0.66 (X2 = 5.00, p = .025). Contrasted with a positive USPSTF risk screening, MAP predicted preeclampsia with slightly improved sensitivity (67 vs. 66%) and negative predictive value (95 vs. 94%), but marginally poorer specificity (65 vs. 67%) and positive predictive value (18 vs. 19%).
Conclusions
Early pregnancy MAP is a modest predictor of preeclampsia and has somewhat improved characteristics as a screening test relative to the USPSTF risk screening algorithm. Moving forward, our early pregnancy MAP threshold may be considered as an adjunct for preeclampsia risk stratification.