Cookie policy: This site uses cookies (small files stored on your computer) to simplify and improve your experience of this website. Cookies are small text files stored on the device you are using to access this website. For more information please take a look at our terms and conditions. Some parts of the site may not work properly if you choose not to accept cookies.

Join

Subscribe or Register

Existing user? Login

Venous thromboembolism

Newer contraceptive pills associated with higher risk of clots

An observational study has found women exposed to newer progestogen-containing contraceptives had a four times increased risk of developing clots.

Newer contraceptive pills linked to higher risk of clots

Source: Scott Camazine / Alamy

Researchers found that the number of additional venous thromboembolism (pictured) cases in treated women was highest for desogestrel and cyproterone

Combined contraceptive pills containing one of the newer progestogens are associated with a higher risk of venous thromboembolism (VTE) than pills containing older progestogens, a study published in The BMJ[1] on 26 May 2015 has found.

The increased clot risk associated with combined oral contraceptives is well known, but previous studies have used different methods to examine this link, meaning the relative risks associated with different hormone combinations have been unclear. 

To address this, researchers from the University of Nottingham used prescription data from two large UK general practice databases to measure the associations between use of different types of combined oral contraceptives and risk of VTE in women aged 15-49 years, adjusting for other known risk factors. A total of 1,340 practices were covered by the two databases from which 10,562 eligible VTE cases were identified and matched with 42,034 controls. 

The results showed that current users of any combined oral contraceptive had a threefold increased risk of VTE compared with non-users of similar age and health status (adjusted odds ratio 2.97, 95% confidence interval 2.78 to 3.17). 

When different pill combinations were looked at, women using combined pills containing older progestogens (levonorgestrel, norethisterone and norgestimate) had around a two and a half times increased risk of VTE compared with women not using any form of pill, while women using pills containing newer progestogens (drospirenone, desogestrel, gestodene and cyproterone) had around a four times increased risk of VTE. 

In absolute terms, the number of extra VTE cases per year per 10,000 treated women was lowest for levonorgestrel and norgestimate (six extra cases), and highest for desogestrel and cyproterone (14 extra cases). 

Around 28% of women in the UK use oral contraceptive pills and the authors stress that combined contraceptive pills are remarkably safe, emphasising that the three times increased risk of VTE in women using oral contraceptives reported in their study is far lower than the ten-fold increased risk of VTE in pregnant women. 

Yana Vinogradova, research fellow in medical statistics at the University of Nottingham, says women on combined contraceptive drugs “should not stop using them, but should consult their doctor and review their current type of pill at their next appointment if they have any concerns”. 

In an accompanying editorial[2], Susan Jick, a professor of epidemiology at Boston University school of public health, says the study “addresses important questions about the risk of VTE in women taking oral contraceptives, concluding that the risk is around twofold higher than the risk associated with older contraceptives”. 

These results, in addition to those of a similar Danish study[3] published in 2011, “clarify inconsistencies in earlier studies and provide important guidance for the safe prescribing of oral contraceptives,” she adds. 

Valerie Beral, professor of epidemiology and director of the cancer epidemiology unit at the University of Oxford, says: “There is nothing new about these findings – they just confirm what we have known for more than two decades now. The MHRA [Medicines and Healthcare products Regulatory Agency] have prescribing guidelines directly relevant to the issue, which already incorporate previous evidence, and which were updated quite recently.” 

Helen Stokes-Lampard, from the Royal College of GPs, says: “The second generation combined oral contraceptive pill is associated with a slightly lower risk of complications of thromboembolism than the newer, third generation pills. But this must be kept in perspective as the newer pills have some other advantages over second generation pills in terms of fewer side effects, so a decision specific to that patient’s needs and her previous experiences should be made.” 

Citation: The Pharmaceutical Journal DOI: 10.1211/PJ.2015.20068627

Have your say

For commenting, please login or register as a user and agree to our Community Guidelines. You will be re-directed back to this page where you will have the ability to comment.

Recommended from Pharmaceutical Press

  • MCQs in Clinical Pharmacy

    MCQs in Clinical Pharmacy

    Four practice tests, each with 80 practice-oriented MCQs. Assess your knowledge of clinical issues, evaluative and analytical skills.

    £25.00Buy now
  • Lecture Notes in Pharmacy Practice

    Lecture Notes in Pharmacy Practice

    A comprehensive study guide which summarises the basic principles in pharmacy practice. Clear, bulleted information for quick reference.

    £43.00Buy now
  • Good Pharmacovigilance Practice Guide

    Good Pharmacovigilance Practice Guide

    An essential guide on pharmacovigilance of medicinal products for human use. Practical advice for developing effective pharmacovigilance systems.

    £38.00Buy now
  • MCQs in Pharmacy Practice

    MCQs in Pharmacy Practice

    A study aid with 800 MCQs. Assess your knowledge, analytical skills, and ability to apply this knowledge base in clinical practice.

    £25.00Buy now
  • Developing Your Prescribing Skills

    Developing Your Prescribing Skills

    Developing Your Prescribing Skills uses case studies, mind maps and feedback from experienced prescribers. It supplies practical advice on the issues facing prescribers in all types of practice.

    £23.00Buy now

Search an extensive range of the world’s most trusted resources

Powered by MedicinesComplete
  • Print
  • Share
  • Comment
  • Save
  • Print Friendly Version of this pagePrint Get a PDF version of this webpagePDF

Supplementary images

  • Newer contraceptive pills linked to higher risk of clots

Jobs you might like

Newsletter Sign-up

Want to keep up with the latest news, comment and CPD articles in pharmacy and science? Subscribe to our free alerts.