Abstract P186: Position Effects Blood Pressure Measurement During Pregnancy

Hypertension in pregnancy is a leading cause of maternal morbidity and mortality. Studies demonstrate that body positions affect the blood pressure (BP) measurements and have led to guidelines for proper positioning by the ACC and AHA. However, studies excluded pregnant women and did not include all common patient positions, such as semi-Fowlers. These studies cannot be applied to pregnant women due to dynamic cardiovascular changes in pregnancy. We measured BP in pregnant women in inpatient and outpatient settings in various positions. These BPs were compared to the published ACC/AHA guideline position: seated with arms and feet supported. Trained team members used an aneroid sphygmomanometer and stethoscope and/or a validated electronic BP machine. There is no significant difference between BP measurements using a sphygmomanometer/stethoscope vs. an electronic BP machine in the ACC/AHA guideline position (systolic p=0.60 diastolic p=0.91). There was not a significant difference in either systolic or diastolic means in the semi-Fowlers position (at 45 degrees measured by goniometer) (systolic=0.60 diastolic=0.95). Positioning did affect the diastolic BP measurement in the seated without support position (p=0.01) and both the systolic (p< 0.001) and diastolic (p<0.001) measurements in the left lateral recumbent position. Our data demonstrate that an accurate BP measurement in pregnancy is dependent upon patient position. Monitoring BP position in left lateral recumbent may mask an elevated BP. This study also suggests that it may be possible to substitute semi-Fowlers position for reliable BP measurements when chair sitting is not practical, such as labor.