Assessment of blood pressure discrepancies in third-trimester hypertensive gravidas

Previous studies have associated hypertension with discrepancies between right arm and left arm blood pressure (BP) measurements. The purpose of this study was to determine if there were clinically (defined as > or = 10 mm Hg disparity) and statistically significant differences between right arm and left arm BP measurements (systolic, diastolic, or mean) in 34 third-trimester hypertensive gravidas. Thirty-four third-trimester normotensive gravidas were used as controls. No subjects were in active labor. This study used a cross-sectional, 2-group design with convenience sampling. The protocol for BP measurement followed guidelines of the American Heart Association and the instrument manufacturer. The results showed a greater range in BP differences between arms for the hypertensive group in the systolic (0.67-26.67 mm Hg) and mean (0.25-67 mm Hg) pressures compared with the normotensive group (systolic, 0-14.33 mm Hg; mean, 0-12 mm Hg). The mean difference in BP between arms was greater for the hypertensive group compared with the normotensive group. Using a 1-tailed t test, the mean difference was statistically significant (P < or = .05) for the systolic pressure (P = .027) and for the mean pressure (P = .022), but not the diastolic pressure (P = .168). The frequency of clinically significant differences (> or = 10 mm Hg) was greater for the hypertensive group than for the normotensive group (13 vs 4). These differences in frequencies were not statistically significant with chi-square analysis (systolic, P = .074; diastolic, P = .303; mean, P = .303). These findings indicated BP discrepancies between arms exist in both normotensive and hypertensive gravidas, with a greater range and frequency of differences in the hypertensive group. This study supports the American Heart Association's recommendation of bilateral BP assessment.