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Sunday 20th May 2018

Risk of blood clots caused by the combined contraceptive pill is still very low

14th August 2009

According to today’s news reports, two studies published in the British Medical Journal suggest that oral contraceptives may cause thrombosis, and many women do not use the safest brands.  Leading sexual health agency Marie Stopes International (www.mariestopes.org.uk) makes the following statement:

“Today’s news reports need to be put into context.  Although blood clots can be a serious side effect of taking combined oral contraceptives, they are extremely rare and should not put women off using the pill.

“We are extremely concerned that women might stop using their prescribed contraceptive pill because they are worried about the risk of blood clots.  In the mid 1990s a particular pill was linked to an increased risk of venous thromboembolism and many women stopped taking it.  As a result, there was an increase in the number of women facing an unplanned pregnancy and seeking abortion advice or services.

“Our advice to women who have any concerns about taking the oral contraceptive pill is not to stop using it, but to make an appointment to discuss the risks with their GP or family planning clinic.

“When considering the increased risk of blood clots associated with oral contraceptive pills, it is important to keep in mind the low incidence rate.  The risk of blood clots in women using the contraceptive pill is considerably less than the risk of blood clots associated with pregnancy.  For example, studies showed that the incidence of venous thrombosis was 8 per 100,000 a year in women who were not pregnant or using oral contraceptive pills compared to 85 per 100,000 in women who had live births with pregnancies of 24 or more weeks of gestation[1].

“Combined oral contraceptive pills are an extremely reliable method of preventing unplanned pregnancy, being more than 99% effective if taken correctly.  Contraceptive pills might be a particularly good contraceptive choice for healthy women who can remember to take their pill.   Combined oral contraceptives are not suitable for every woman, but risks differ dependent on each individual’s medical history.  For example, combined contraceptive pills should not be taken by women with conditions such as high blood pressure, or women who smoke.

“There are over 15 methods of contraception available in the UK, so if a woman has any concerns about using the contraceptive pill, she might like to consider alternative options to best suit her individual needs and lifestyle.  Progestogen only methods, such as the progestogen only pill and long acting reversible methods such as hormone releasing intrauterine devices are not associated with an increased risk of blood clots.  A woman should visit her GP, family planning centre or a specialist organisation such as Marie Stopes International for further information and advice.



All quotes are attributable to Liz Davies, Director UK and Europe, Marie Stopes International.

The studies published in the British Medical Journal are available via:




1. Risks of Oral Contraceptive Pills: The Risk of Venous Thromboembolic Disease Associated With the Use of Oral Contraceptive Pills, accessed via: http://www.medscape.com/viewarticle/421027_4 August 2009

Marie Stopes International is a specialist organisation providing expert and confidential care and support to clients in relation to their sexual and reproductive healthcare, including contraceptive consultations and provision of a variety of contraceptive methods.  MSI provides a 24 hour information line to offer advice and assistance: 0845 300 8090.  For further information visit www.mariestopes.org.uk    


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