First Trimester Mean Arterial Pressure Measured Manually Versus Using an Automated Device and the Prediction of Preeclampsia: A Case-Cohort Study

Objective: First trimester mean arterial blood pressure (MAP) can be used to predict preeclampsia. This study aimed to compare the performance of first trimester MAP measured with an automated device using a standardized technique versus MAP taken manually in a typical clinical setting.

Methods: A case-cohort study niched into a prospective cohort of pregnant women recruited at 11-14 weeks was performed. MAP was measured with an automated device on both arms until stability was reached. These results were compared with the MAP measured with a manual device at the closest medical visit (between 10 and 15 weeks gestation) and noted in the medical charts. Receiver-operator characteristics curve analyses were used to estimate the predictive values of MAP measured by both techniques.

Results: Forty-one women with preeclampsia and 167 control patients were used for the comparisons. MAP measured with an automated device decreased significantly between 11 and 14 weeks gestation (P < 0.001). Moreover, MAP measured with an automated device was a better predictor of preeclampsia (area under the curve 0.70; 95% confidence interval 0.61-0.79) than MAP measured with a manual device in a clinical setting (area under the curve 0.60; 95% confidence interval 0.50-0.70). Taken alone, MAP measured with an automated device was associated with a detection rate of preeclampsia of 34%, for a false-positive rate of 10%.

Conclusion: First trimester MAP can predict preeclampsia. This study demonstrated that MAP measured with an automated device using a standardized technique is a better predictor than MAP measured with a manual device.