Evidence map›Paper›PMID 31856759›Full record

SynthesisBMC pregnancy and childbirth2019

Plasma volume expansion across healthy pregnancy: a systematic review and meta-analysis of longitudinal studies.

Sixtus Aguree, Alison D Gernand

Abstract readMeta-AnalysisSystematic Review
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in BMC pregnancy and childbirth, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 93 papers, 3 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
93citing papers in PubMed, 3 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

93 citing papers in PubMed, 3 syntheses or guidelines pooled it.

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33 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

2 authors.

Sixtus Aguree110 Chandlee Laboratory, Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, 16802, USA.
Alison D Gernand110 Chandlee Laboratory, Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, 16802, USA. adg14@psu.edu.ORCID http://orcid.org/0000-0002-5661-7785

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundPlasma volume expansion is an important physiologic change across gestation. High or low expansion has been related to adverse pregnancy outcomes, yet there is a limited understanding of normal/healthy plasma volume expansion. We aimed to evaluate the pattern of plasma volume expansion across healthy pregnancies from longitudinal studies.

methodsWe conducted a systematic review and meta-analysis to identify original studies that measured plasma volume in singleton pregnancies of healthy women. Specifically, we included studies that measured plasma volume at least two times across gestation and one time before or after pregnancy in the same women. PubMed, Web of Science, Cochrane, CINAHL, and clinicaltrials.gov databases were searched from the beginning of each database to February 2019. We combined data across studies using a random effects model.

resultsTen observational studies with a total of 347 pregnancies were eligible. Plasma volume increased by 6% (95% CI 3-9) in the first trimester compared to the nonpregnant state. In the second trimester, plasma volume was increased by 18% (95% CI 12-24) in gestational weeks 14-20 and 29% (95% CI 21-36) in weeks 21-27 above the nonpregnant state. In the third trimester, plasma volume was increased by 42% (95% CI 38-46) in weeks 28-34 and 48% (95% CI 44-51) in weeks 35-38. The highest rate of increase occurred in the first half of the second trimester. Included studies were rated from moderate to high quality; 7 out of 10 studies were conducted over 30 years ago.

conclusionsIn healthy pregnancies, plasma volume begins to expand in the first trimester, has the steepest rate of increase in the second trimester, and peaks late in the third trimester. The patterns observed from these studies may not reflect the current population, partly due to the changes in BMI over the last several decades. Additional longitudinal studies are needed to better characterize the range of normal plasma volume expansion across maternal characteristics.

Indexed as

FemaleHumansLongitudinal StudiesPlasma VolumePregnancyReference ValuesEvans blue dyeGestationHemodilutionPlasma volume expansionPregnancy

Identifiers

PMID31856759
PMCPMC6924087

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.