Validation of the Microlife WatchBP Home blood pressure device in pregnancy for medium and large arm circumferences

OBJECTIVE: The Microlife WatchBP Home automated blood pressure device was assessed for accuracy in pregnant women of medium (<32 cm) and large (≥32 cm) arm circumference. MATERIALS AND METHODS: The British Hypertension Society validation protocol was modified for the purpose of this study to include women with arm circumference of less than 32 cm (N=51) and greater than or equal to 32 cm (N=46) as two separate arms. RESULTS: The device achieved an overall A/A grade for medium arm circumference and B/A grade for large arm circumference. The mean±SD device-observer difference was 1.7±6.2 and -0.4±4.4 for systolic and diastolic blood pressure, respectively, for medium arm circumference and 3.0±8.5 and 1.5±5.1, respectively, for large arm circumference. When all women with pre-eclampsia from both groups were pooled (N=23), the device achieved an overall grade of A/A with mean differences of 2.1±7.2 for systolic blood pressure and 1.0±5.6 for diastolic blood pressure. CONCLUSION: The Microlife WatchBP Home automated blood pressure device can be recommended for use in pregnant women of all gestations, including those with pre-eclampsia. However, caution is needed for women with large arm circumferences.