Cuff width influence on blood pressure measurement during the pregnant-puerperal cycle

BACKGROUND: The correct evaluation of blood pressure (BP) during pregnancy is a crucial factor in the prevention of eclampsia. Following American Heart Association (AHA) guidelines to employ a correct cuff width (CCW), 20% larger than arm diameter, we demonstrate that the standard cuff width (SCW), 12 cm wide, is too large for lean women causing underestimation of BP. AIMS: To identify the arm circumference (AC) in pregnant women and the corresponding cuff width; to compare BP records from CCW vs. SCW; and to identify under- and overestimation of BP in SCW reading. DESIGN: A follow up study of BP was performed in 104 pregnant women using two cuffs widths (CCW vs. standard one). The investigation was carried out during all antenatal appointments and postpartum stage in two maternity hospitals. In every appointment BP was registered three times with each type of cuff; and the means of those three readings were compared. METHODS: The CCW for each woman was selected according to AHA recommendation for cuff width size (20% larger than arm diameter), which was based on the classical European and North-American studies. Results. Arm circumference varied from 20 to 38 cm requiring a cuff width from 8 to 14 cm. The CCW most employed was 10 cm wide. The SCW (12 cm) was employed as CCW in only 13.4% of the subjects. Statistical difference was found on BP means when comparing both cuffs (P < 0.05), reaching 23 mmHg in systolic values and 20 in diastolic ones. Such differences showed a serious underestimation when SCW was employed in 80.8% of the subjects and overestimation in 5.8% of obese subjects. CONCLUSION: Our findings showed that the SCW underestimates BP of pregnant women. Our hypothesis is that such underestimation may lead to the misdiagnosis of pre-eclampsia, particularly in lean pregnant women.