No difference between home and clinic blood pressure measurements in pregnancy: a computerized telemetric study.

Many decisions in pregnancy are based on one or two casual blood pressure estimations made in the antenatal clinic. No previous study has challenged the validity of this practice or attempted to discover whether there are significant differences between the blood pressures of pregnant women when they are measured in the clinic and when they are measured in their home environment. We measured the blood pressures of 35 healthy pregnant women both at the antenatal clinic and in their own homes. All the women were at between 28 and 32 weeks gestation. At both locations, ten consecutive blood pressure and pulse measurements were made at one minute intervals using a Dinamap 1846P automated blood pressure monitor. The readings taken in the clinic were supervised, whilst at home the patients used our blood pressure telemetry system without direct supervision, the results being transmitted automatically to the hospital computer via the public telephone network. The Dinamap results were analysed in detail. Each ten minute recording session was summarised in terms of the first, last, highest, lowest and mean of the systolic, diastolic and mean arterial blood pressure, and pulse measurements in that session. Also, two measures of the variability within a ten measurement series were considered, the average change in pressure or pulse from one reading to the next, and the difference between the highest and lowest readings of pressure and pulse in the series. All descriptors of the clinic and the home measurements were compared using the paired Student's t-test. Clinic and home blood pressure measurements were not significantly different from each other in any respect.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood pressure measured telemetrically from home throughout pregnancy.

Sixty-eight healthy pregnant women measured their blood pressure at home for 1 day every 4 weeks from 14 weeks' gestation until delivery. Blood pressure measurements were made with the Cambridge blood pressure telemetry system, which was composed of a Dinamap 1846 monitor linked to and controlled by a dedicated microprocessor which communicated transtelephonically with a hospital-based microcomputer. On each measurement day each woman measured her blood pressure five times: on first rising and then at 10 AM, 2 PM, 6 PM and 10 PM. At each measurement session the blood pressure was automatically taken 10 times at 1-minute intervals. A total of 23,790 individual blood pressure measurements were analyzed. Systolic, diastolic, and mean arterial blood pressures were lowest at 18 weeks' gestation, rising slowly thereafter at a rate of 0.4 mm Hg systolic and 0.2 mm Hg diastolic per week. The maternal pulse rate also increased steadily after 18 weeks at a rate of 0.25 beats/min per week. There was a strong correlation between the blood pressures at 18, 26, and 38 weeks. All blood pressure parameters were significantly lower on first rising than at other times of the day, although the differences were small: 5 mm Hg for systolic, 4 mm Hg for mean arterial, and 3 mm Hg for diastolic blood pressure. After 10 AM, however, there was no significant daytime variation in any blood pressure parameter, indicating that for most purposes the time of day at which pressure measurements are made is unimportant.