Few studies have explored blood pressure (BP) trends in pregnancy and the postpartum period. The accepted belief is that BP in pregnancy stays close to non-pregnant values (120/80mmHg). Studies also suggest variance between clinic and home based BP measurements. In this report, we describe the use of digital health technology to gather weekly BP values and better track BP trends in pregnancy.
Retrospective analysis was conducted of pregnant patients enrolled in the first trimester from 12 university-affiliated clinics. Patients received a digital sphygmomanometer and were asked to check home-based blood pressure at least weekly. BP averages were categorized by pre-pregnancy body mass index (BMI).
381 patient records had complete blood pressure data for the entire pregnancy totaling 8101 data points. Mean systolic BP was 101 mmHg (±11.3) for BMI < 18.5, 106 mmHg (±10.8) for BMI 18.5-24.9, 112 mmHg (±10.6) for BMI 25-29.9, 117 mmHg (±11) for BMI 30+. An ANOVA analysis demonstrated significant differences between weight classes (p < 2.8e-34). Mean systolic BP was higher in clinic vs at home except in the obese class.
Mean systolic BP may be lower in pregnancy and increases significantly with increasing BMI. BP collected at home is frequently lower than clinic measurements and may be a more accurate reflection of “normal” BP. We plan to analyze this data to identify norms for each trimester. Further study of high frequency at-home BP monitoring is needed to improve our understanding of blood pressure trends in pregnancy.