Blood pressure levels correlate with intra-individual variability using an automated device in early pregnancy

Comparison of clinic and home blood pressure readings in higher risk pregnancies - Secondary analysis of the BUMP 1 trial

OBJECTIVE

To compare clinic and home blood pressure readings in higher risk pregnancies in the antenatal period from 20 weeks gestation, and to evaluate differences between the two modalities.

STUDY DESIGN

A cohort study comprising a secondary analysis of a large randomised controlled trial (BUMP 1).

POPULATION

Normotensive women at higher risk of pregnancy hypertension randomised to self-monitoring of blood pressure.

MAIN OUTCOME MEASURES

The primary outcome was the overall mean difference between clinic and home readings for systolic blood pressure (sBP) and diastolic blood pressure (dBP). Blood pressure readings were averaged across each gestational week for each participant and compared within the same gestational week. Calculations of the overall differences were based on the average difference for each week for each participant.

RESULTS

The cohort comprised 925 participants. In total, 92 (10 %) developed a hypertensive disorder during the pregnancy. A significant difference in the overall mean sBP (clinic - home) of 1.1 mmHg (0.5-1.6 95 %CI) was noted, whereas no significant difference for the overall mean dBP was found (0.0 mmHg (-0.4-0.4 95 %CI)). No tendency of proportional bias was noted based on Bland-Altman plots. Increasing body mass index in general increased the difference (clinic - home) for both sBP and dBP in a multivariate analysis.

CONCLUSIONS

No clinically significant difference was found between clinic and home blood pressure readings in normotensive higher risk pregnancies from gestational week 20+0 until 40+0. Clinic and home blood pressure readings might be considered equal during pregnancy in women who are normotensive at baseline.

First Trimester Mean Arterial Pressure Measured Manually Versus Using an Automated Device and the Prediction of Preeclampsia: A Case-Cohort Study

OBJECTIVE

First trimester mean arterial blood pressure (MAP) can be used to predict preeclampsia. This study aimed to compare the performance of first trimester MAP measured with an automated device using a standardized technique versus MAP taken manually in a typical clinical setting.

METHODS

A case-cohort study niched into a prospective cohort of pregnant women recruited at 11-14 weeks was performed. MAP was measured with an automated device on both arms until stability was reached. These results were compared with the MAP measured with a manual device at the closest medical visit (between 10 and 15 weeks gestation) and noted in the medical charts. Receiver-operator characteristics curve analyses were used to estimate the predictive values of MAP measured by both techniques.

RESULTS

Forty-one women with preeclampsia and 167 control patients were used for the comparisons. MAP measured with an automated device decreased significantly between 11 and 14 weeks gestation (P < 0.001). Moreover, MAP measured with an automated device was a better predictor of preeclampsia (area under the curve 0.70; 95% confidence interval 0.61-0.79) than MAP measured with a manual device in a clinical setting (area under the curve 0.60; 95% confidence interval 0.50-0.70). Taken alone, MAP measured with an automated device was associated with a detection rate of preeclampsia of 34%, for a false-positive rate of 10%.

CONCLUSION

First trimester MAP can predict preeclampsia. This study demonstrated that MAP measured with an automated device using a standardized technique is a better predictor than MAP measured with a manual device.