Precision, consistency, and reproducibility of blood pressure in diabetic and non-diabetic pregnancy: the appraisal of repeated measurements.

A monitor (Spacelab 90207) was compared with sphygmomanometric blood pressure (BP) with respect to reproducibility and variations on precision and consistency. Some 133 women with type 1 diabetes mellitus and 59 non-diabetic women were recruited. During pregnancy, systolic BP was between 6 and 12 mmHg higher in the oscillometric than the auscultatory readings, and diastolic BP was between 1 and 2.6 mmHg. The association of difference with the mean BP disappeared with progression of pregnancy and the repetition of measurements in diabetic pregnancy. The precision, reproducibility, and trend of association over the scale of measurement were improved in the repeated compared to individual measurements, whereas consistency did not improve.