AMBULATORY BLOOD-PRESSURE MONITORING DURING PREGNANCY - COMPARISON WITH MERCURY SPHYGMOMANOMETRY

There is little information concerning the relationship between blood pressures obtained by standard mercury sphygmomanometry and ambulatory blood pressure monitoring (ABPM) in pregnancy. We compared readings obtained with these two methods using an Hawksley random zero mercury sphygmomanometer and an Accutracker II ABPM device. Blood pressures were compared over 90 min with the pregnant woman seated and, in a separate study, over 30 min during standing and ambulation. When pregnant women were seated, the ABPM overestimated the systolic blood pressure (BP) by 5 (3,6) mm Hg (mean, 95% confidence limits) (P < .001) and underestimated diastolic phase IV readings by 7 (- 9, - 6) mm Hg W < .001) and phase V readings by 3 (- 5, - 1) mm Hg (P < .01). Eighty-three percent of systolic readings agreed within 10 mm Hg. Seventy-six percent of diastolic phase V (but only 45% of phase IV) readings agreed within 6 mm Hg. When pregnant women were ambulatory, the ABPM overestimated systolic BP by 7 (4,10) mm Hg (P < .001) and underestimated diastolic phase IV readings by 6 (- 8, - 4) mm Hg W < .001) and phase V readings by 4 (- 6, - 2) mm Hg (P < .01). Eighty percent of systolic readings agreed within 10 mm Hg. Fifty-five percent of diastolic phase V and 50% of diastolic phase IV readings agreed within 6 mm Hg. The Accutracker II blood pressure readings are reasonably comparable to those of mercury sphygmomanometry in pregnant women, particularly when assessing group data. Such devices must be compared with mercury recordings in individual pregnant women before they are applied to clinical practice.