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Trends of blood pressure and heart rate in normal pregnancies: a systematic review and meta-analysis

Abstract:

Background: Current reference ranges for blood pressure and heart rate throughout pregnancy have a poor evidence base.

Methods: Systematic review and meta-analysis: We included studies measuring blood pressure or heart rate from healthy pregnant women within defined gestational periods of sixteen-weeks or less. We analysed systolic blood pressure, diastolic blood pressure and heart rate by gestational age. We assessed effects of measurement year and method.

Results: We included 39 studies undertaken 1967-2017, containing 124,349 systolic measurements from 36,239 women, 124,291 diastolic measurements from 36,181 women and 10,948 heart rate measurements from 8317 women. Mean (95% CI) systolic blood pressure was lowest at 10 weeks gestation, 110.4 (108.5, 112.3) mmHg, rising to 116.0 (113.6, 118.4) mmHg at 40 weeks, mean (95% CI) change 5.6 (4.0, 7.2) mmHg. Mean (95% CI) diastolic blood pressure was lowest at 21 weeks gestation, 65.9 (64.2, 67.7) mmHg; rising to 72.8 (71.0, 74.6) mmHg at 40 weeks, mean (95% CI) change 6.9 (6.2, 7.5) mmHg. Mean (95% CI) heart rate rose from 79.3 (75.5, 83.1) beats/min at 10 weeks to 86.9 (82.2, 91.6) beats/min at 40 weeks gestation, mean (95% CI) change 7.6 (1.8, 13.4) beats/min. Studies using manual measurement reported higher diastolic blood pressures than studies using automated measurement, mean (95 CI) difference 4.9 (0.8, 8.9) mmHg. Diastolic blood pressure increased by 0.26 (95% CI 0.10-0.43) mmHg /year. Including only higher quality studies had little effect on findings, with heterogeneity remaining high (I2 statistic >50%).

Conclusions: Significant gestational blood pressure and heart rate changes occur that should be taken into account when assessing pregnant women. Commonly taught substantial decreases in blood pressure mid-pregnancy were not seen and heart rate increases were lower than previously thought. Manual and automated blood pressure measurement cannot be used interchangeably. Increases in diastolic blood pressure over the last half-century and differences between published studies show contemporary data are required to define current normal ranges.

Publication status:
Published
Peer review status:
Peer reviewed

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Publisher copy:
10.1186/s12916-019-1399-1

Authors


More by this author
Institution:
University of Oxford
Division:
MPLS Division
Department:
Engineering Science
Role:
Author
More by this author
Institution:
University of Oxford
Division:
MPLS Division
Department:
Engineering Science
Role:
Author
More by this author
Institution:
University of Oxford
Division:
Medical Sciences Division
Department:
Centre for Statistics in Medicine
Role:
Author
More by this author
Institution:
University of Oxford
Division:
Medical Sciences Division
Department:
Primary Care Health Sciences
Role:
Author
More by this author
Institution:
University of Oxford
Division:
Medical Sciences Division
Department:
Women's and Reproductive Health
Role:
Author


Publisher:
Bio Med Central
Journal:
BMC Medicine More from this journal
Volume:
17
Issue:
2019
Article number:
167
Publication date:
2019-09-11
Acceptance date:
2019-07-29
DOI:
ISSN:
1741-7015


Keywords:
Pubs id:
pubs:1035928
UUID:
uuid:eab5e6e4-6fac-47e1-9629-10accfc5bebc
Local pid:
pubs:1035928
Source identifiers:
1035928
Deposit date:
2019-07-29

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