Inter-arm asymmetry in systolic and diastolic blood pressure measurements among normotensive primigravidae

Introduction: The detection of elevated BP during pregnancy is one of the major aspects of optimal antenatal care,and thus accurate measurement of BP is essential. Methods: To evaluate whether there is a significant difference in inter-arm blood pressure (BP) measurements among normotensive low-risk primigravidae as an observational study was conducted at Yediur Municipal Maternity Corporation Hospital, Bangalore. A total of 100 low-risk women at 6-14 weeks of gestation attending antenatal clinic was selected by purposive sampling technique. Bilateral BP was measured by a calibrated Normal mercury Sphygmomanometer during the initial antenatal visit and the subsequent 2 months visits. Mean Inter-arm systolic blood pressure (SBP) and diastolic blood pressure (DBP) differences were computed for each visit and the three pairs of readings were averaged to obtain a mean SBP and DBP for each arm to derive the mean inter-arm difference. Results: The results revealed a significant difference in the mean SBP in right (115.71 ± 0.827 standard deviation [SD]) versus left arm (105.23 ± 1.110 SD) and the mean DBP in right (73.10 ± 0.370 SD) versus left arm (69.43 ± 2.288) at P < 0.001. For SBP, the mean difference between the right and left arm was 11.87 mmHg, and the normal range was 2 mmHg to 16 mmHg. For DBP, the mean difference was 6.09 mmHg, and the normal range was 0 mmHg to 10 mmHg. Twenty-one (n = 21) primigravidae had clinically important differences >10 mmHg in SBP and DBP between their arms. None of the maternal characteristics were a significant predictor of inter-arm SBP and DBP differences at P > 0.001. Conclusion: Assessment of bilateral BP should become a routine part of cardiovascular assessment of pregnant women in primary care to determine whether the risk to the pathological condition is present.