Evidence map›Paper›PMID 19679614›Full record

ArticleBMJ (Clinical research ed.)2009

The venous thrombotic risk of oral contraceptives, effects of oestrogen dose and progestogen type: results of the MEGA case-control study.

A van Hylckama Vlieg, F M Helmerhorst, J P Vandenbroucke, C J M Doggen, F R Rosendaal

Open access · hybridAbstract readMulticenter Study
PubMed Full text at PMC Publisher
In one paragraph

Article in BMJ (Clinical research ed.), 2009. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 155 papers, 10 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
155citing papers in PubMed, 10 pooled it
59.2field-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

155 citing papers in PubMed, 10 syntheses or guidelines pooled it, 655 citations in OpenAlex.

  1. Pooled it
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  3. A systematic review and meta-analysis of venous thrombosis risk among users of combined oral contraception.International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics · 2018
    Pooled it
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  6. Combined oral contraceptives: venous thrombosis.The Cochrane database of systematic reviews · 2014
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  10. Triphasic versus monophasic oral contraceptives for contraception.The Cochrane database of systematic reviews · 2011
    Pooled it
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  19. Budd-Chiari Syndrome: Presentation, Management, and Prognosis.The American journal of gastroenterology · 2026
    Review
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95 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

5 authors at 1 institution in 1 country.

A van Hylckama VliegDepartment of Clinical Epidemiology, Leiden University Medical Center, C7-P, PO Box 9600, NL-2300 RC Leiden, Netherlands.
F M Helmerhorst
J P Vandenbroucke
C J M Doggen
F R Rosendaal
Leiden University Medical Center · NL

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

objectiveTo assess the thrombotic risk associated with oral contraceptive use with a focus on dose of oestrogen and type of progestogen of oral contraceptives available in the Netherlands.

designPopulation based case-control study.

settingSix participating anticoagulation clinics in the Netherlands (Amersfoort, Amsterdam, The Hague, Leiden, Rotterdam, and Utrecht).

participantsPremenopausal women <50 years old who were not pregnant, not within four weeks postpartum, and not using a hormone excreting intrauterine device or depot contraceptive. Analysis included 1524 patients and 1760 controls.

main outcome measuresFirst objectively diagnosed episodes of deep venous thrombosis of the leg or pulmonary embolism. Odds ratios calculated by cross-tabulation with a 95% confidence interval according to Woolf's method; adjusted odds ratios estimated by unconditional logistic regression, standard errors derived from the model.

resultsCurrently available oral contraceptives increased the risk of venous thrombosis fivefold compared with non-use (odds ratio 5.0, 95% CI 4.2 to 5.8). The risk clearly differed by type of progestogen and dose of oestrogen. The use of oral contraceptives containing levonorgestrel was associated with an almost fourfold increased risk of venous thrombosis (odds ratio 3.6, 2.9 to 4.6) relative to non-users, whereas the risk of venous thrombosis compared with non-use was increased 5.6-fold for gestodene (5.6, 3.7 to 8.4), 7.3-fold for desogestrel (7.3, 5.3 to 10.0), 6.8-fold for cyproterone acetate (6.8, 4.7 to 10.0), and 6.3-fold for drospirenone (6.3, 2.9 to 13.7). The risk of venous thrombosis was positively associated with oestrogen dose. We confirmed a high risk of venous thrombosis during the first months of oral contraceptive use irrespective of the type of oral contraceptives.

conclusionsCurrently available oral contraceptives still have a major impact on thrombosis occurrence and many women do not use the safest brands with regard to risk of venous thrombosis.

Indexed as

AdolescentAdultCase-Control StudiesContraceptives, Oral, HormonalContraceptives, Oral, SyntheticEstrogensFemaleHumansMiddle AgedNetherlandsProgestinsPulmonary EmbolismRisk FactorsVenous ThrombosisYoung AdultContraceptives, Oral, HormonalContraceptives, Oral, SyntheticEstrogensProgestins

Identifiers

PMID19679614
PMCPMC2726929
OpenAlexW2137955943

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

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.