Difference in forearm and upper arm blood pressure measurements in prenatal women

Abstract

Background: In health-care services, when bare upper arm blood pressure (BP) measurement is impractical, the forearm may be used as a surrogate for traditional upper arm BP. Objective: This exploratory study aimed to determine the significant difference and correlation between the upper versus forearm BP measurements among low-risk prenatal women. SMaterials and Methods: A total of 156 low-risk prenatal women in the third trimester of pregnancy attending antenatal clinics at Municipal Maternity Corporation Hospitals, Bengaluru, were recruited by purposive sampling. Upper and forearm noninvasive BP (NIBP) measurements obtained by mercury sphygmomanometer, thrice at an interval of 15 min were averaged. The main outcome measures were the significant difference and correlation between the upper arm and forearm BP measurements. Results: The mean systolic BP (SBP) (117.14 ± 3.041 mmHg) and diastolic BP (DBP) (69.31 ± 8.461 mmHg) in the forearm was significantly higher than the upper arm SBP (111.72 ± 5.53; P = 0.002) and DBP (61.46 ± 6.014 mmHg; P = 0.016). The mean difference in SBP between upper and forearm was 5.42 ± 2.016 mmHg and in DBP 7.85 ± 3.204 mmHg. Upper versus forearm BP measurements had revealed a significant positive linear correlation in SBP (r = 0.849; P = 0.013) and DBP (r = 0.816; P = 0.021) by Pearson product-moment correlation coefficient. Clinically 94 (72.31%) had a significant BP measurements difference in forearm versus upper arm by approximately 6–10 mmHg. None of the maternal characteristics were independent predictors for the mean difference in SBP and DBP measurement. Conclusion: Forearm NIBP measurements are higher than the BP obtained at the upper arm location. This must be taken into consideration whenever the forearm is used as an alternative site for the upper arm BP.