Automated blood pressure measurements in laboring women: are they reliable?

In laboring women a consistent difference has become evident between measurements obtained with an automated blood pressure device and those obtained with the auscultatory method. A prospective study was designed to assess the concordance of these two methods.

Three sets of brachial blood pressure measurements were made by both oscillatory and auscultatory techniques in 30 women in labor, 20 term pregnant women not in labor, and 20 nonpregnant volunteers.

In the nonlaboring women and the nonpregnant controls there was satisfactory agreement between the results of the two methods of measurement. In the parturients systolic pressures were consistently and significantly higher and diastolic pressures consistently and significantly lower with the oscillatory compared with the auscultatory method, but mean arterial pressures were not different.

In laboring women there is a discrepancy between systolic and diastolic pressures obtained by the auscultatory versus the oscillatory method of measurement, although mean pressures are not significantly different. We suggest that during labor the diagnoses of hypertension and hypotension be based on the mean rather than the systolic or diastolic pressure.