Evidence map›Paper›PMID 22021762›Full record

ArticleBMJ open2011

Population-based trends in pregnancy hypertension and pre-eclampsia: an international comparative study.

Christine L Roberts, Jane B Ford, Charles S Algert, Sussie Antonsen, James Chalmers, Sven Cnattingius, Manjusha Gokhale, Milton Kotelchuck, Kari K Melve, Amanda Langridge and 8 more

Open access · goldAbstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in BMJ open, 2011. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 117 papers, 11 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
117citing papers in PubMed, 11 pooled it
15.7field-weighted citation impact, top 1% of its field
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

117 citing papers in PubMed, 11 syntheses or guidelines pooled it, 294 citations in OpenAlex.

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  6. Guided imagery for treating hypertension in pregnancy.The Cochrane database of systematic reviews · 2019
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57 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

18 authors at 11 institutions in 7 countries.

Christine L RobertsPerinatal Research, Kolling Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia. clroberts@med.usyd.edu.au
Jane B Ford
Charles S Algert
Sussie Antonsen
James Chalmers
Sven Cnattingius
Manjusha Gokhale
Milton Kotelchuck
Kari K Melve
Amanda Langridge
Carole Morris
Jonathan M Morris
Natasha Nassar
Jane E Norman
John Norrie
Henrik Toft Sørensen
Robin Walker
Christopher J Weir
University of Sydney · AUAarhus University Hospital · DKBoston University · USNational Health Service Scotland · GBKarolinska Institutet · SEMRC Centre for Reproductive Health · GBThe Kids Research Institute Australia · AUUniversity of Bergen · NOUniversity of Calgary · CAUniversity of Edinburgh · GBUniversity of Glasgow · GB

Funding

Medical Research Council G0800803Medical Research Council G1002033
6 · The paper itself

Abstract

objectiveThe objective of this study was to compare international trends in pre-eclampsia rates and in overall pregnancy hypertension rates (including gestational hypertension, pre-eclampsia and eclampsia).

designPopulation data (from birth and/or hospital records) on all women giving birth were available from Australia (two states), Canada (Alberta), Denmark, Norway, Scotland, Sweden and the USA (Massachusetts) for a minimum of 6 years from 1997 to 2007. All countries used the 10th revision of the International Classification of Diseases, except Massachusetts which used the 9th revision. There were no major changes to the diagnostic criteria or methods of data collection in any country during the study period. Population characteristics as well as rates of pregnancy hypertension and pre-eclampsia were compared.

resultsAbsolute rates varied across the populations as follows: pregnancy hypertension (3.6% to 9.1%), pre-eclampsia (1.4% to 4.0%) and early-onset pre-eclampsia (0.3% to 0.7%). Pregnancy hypertension and/or pre-eclampsia rates declined over time in most populations. This was unexpected given that factors associated with pregnancy hypertension such as pre-pregnancy obesity and maternal age are generally increasing. However, there was also a downward shift in gestational age with fewer pregnancies reaching 40 weeks.

conclusionThe rate of pregnancy hypertension and pre-eclampsia decreased in northern Europe and Australia from 1997 to 2007, but increased in Massachusetts. The use of a different International Classification of Diseases coding version in Massachusetts may contribute to the difference in trend. Elective delivery prior to the due date is the most likely explanation for the decrease observed in Europe and Australia. Also, the use of interventions that reduce the risk of pregnancy hypertension and/or progression to pre-eclampsia (low-dose aspirin, calcium supplementation and early delivery for mild hypertension) may have contributed to the decline.

Identifiers

PMID22021762
PMCPMC3191437
OpenAlexW2099856909

What OpenQuestion holds

Textmetadata
LicenceCC BY-NC
Read underepoch 390

Registered trials

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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.