Interpretation
We observed that the CDXP measured blood pressure as reliable as the
Omron M6 Comfort, which has been validated for the use during pregnancy.
We did not find any association between body mass index, gestational
age, upper arm or wrist circumference, or height of blood pressure and
the difference between the CDXP and gold standard. Literature reports
similar ranges of deviation of upper-arm devices22,
24. Although blood pressure measurement using an upper-arm device is
thought to be superior, we did not detect clinically relevant
differences25. The above implies that the CDXP seems
to qualify for the use for home blood pressure monitoring.
Our study showed that OBPM under our regular check-up circumstances
(several minutes after entering the consult room with the physician
present) is significantly higher than the self-measured blood pressure
under more standardized conditions: 5 minutes of rest, sitting in a
chair against the backrest, non-crossed legs placed on the ground and no
physician present. This is in line with literature on pregnant and
non-pregnant individuals 28, 30, 31. ‘White coat
hypertension’ may lead to overdiagnosis of hypertension when blood
pressure is not measured under ideal circumstances 29.
Self-measuring blood pressure with the CDXP helps to meet these
criteria.
The blood pressure used for monitoring and early detection of
pregnancy-related disorders needs to represent the blood pressure during
the day. We observed that HBPM using the CDXP during pregnancy is
completely stable during the day. Self-measured home blood pressure at a
single time point gives a good reflection of the blood pressure during
the day. Several studies show comparable differences between OBPM and
HBPM in both pregnant and non-pregnant subjects 26-28,
32. Our data is also in line with Hermida et al., that demonstrated
that blood pressure is very stable during daytime and drops during the
night 4. This implies that HBPM gives a better
reflection of the actual blood pressure during pregnancy than OBPM.
The success of changing OBPM to self-measured HBPM also depends on user
experience and satisfaction. Our study is in line with previous
literature, where 98% of women with gestational hypertensive disease
liked involvement in their blood pressure management and declared to
have more confidence in HBPM to represent their usual blood
pressure16, 33, 34. Our study showed that pregnant
women liked the idea of self-measuring their blood pressure, they found
the CDXP easy to use and they felt confident about the reliability of
their self-measured blood pressure.