A growing body of research has shown that many Irish women who are taking some of the most popular contraceptive pills risk developing potentially life-threatening blood clots.

While scientific investigations are ongoing, it is suspected that the synthetic oestrogen used in this type of contraceptive may increase the risk of deep vein thrombosis (DVT)

DVT is the formation of a blood clot in a deep vein, which usually occurs in the legs, giving rise to symptoms including pain, swelling, redness, warmness, and engorged superficial veins.

If detected in time embolisms and other complications arising from DVTs can be prevented by appropriate exercise, anticoagulants, aspirin, compression stockings and other medical intervention.

If left untreated DVTs can give rise to a pulmonary embolism which is a potentially life-threatening condition caused by the detachment of a clot which then travels up blood vessels to cause a potentially fatal blockage in the lung. Clots caused by DVTs can also travel to the brain, causing a stroke.

In this country the Irish Medicines Board (IMB) has received notifications of six deaths related to the use of the oral contraceptive pill in Ireland since 1992. Two of those deaths, which were due to clotting-related complications, involved the use of Yasmin and Yaz.

These so-called ‘third generation’ contraceptive products (which have grown popular because they are less likely to cause side effects such as weight gain, headaches, breast tenderness and hair growth) have been linked with fourteen deaths per annum in France.

While fears about the increased risk of DVT have been signalled as far back as 1995, a more recent study carried out in France found that between 2000 and 2011, 2,529 cases of serious blood clots were caused by combined contraceptives. Of these, 1,751 were due to third generation pills such as Yasmin and Femodene.

Britain’s Medicines and Healthcare Products Regulatory Agency (MHRA) has instructed UK doctors to pay careful consideration to women’s individual risk factors before prescribing them the combined hormonal contraceptives. UK GPs must now go through a patient checklist when prescribing the pills with a view to preventing the contraceptive from being given to women with a higher inherent risk of developing blood clots. The French medical authorities have taken a stronger line by ordering doctors to offer the newer third-generation pills only if their patients had first tried and were unhappy with the older offerings. The Irish Medicines Board (IMB) has published an update on the risks associated with third-generation contraceptives but has not issued any additional directions regarding their prescription.

While combined hormonal contraceptives are a highly effective and safe means of preventing unwanted pregnancy in healthy women, there is an obligation on health care professionals to ensure that women who are prescribed the drug are not within any of the categories which would militate against it use.

Having regard to the amount of information now available regarding potential clotting complications, there is an onus on GPs to identify specific risk factors in their patients before prescribing the oral contraceptive pill and to inform them that they are almost twice as likely to develop blood clots if they take some of the most popular birth-control tablets, including Yasmin, Femodene and Marvelon, compared with older products.

There are numerous factors, including:

• being older;
• being overweight or obese;
• being a smoker;
• having a history of deep vein thrombosis; or
• suffering from high blood pressure;

which should prevent a doctor from recommending or prescribing these drugs to women.

Bayer, which is the pharmaceutical company that manufactures both Yasmin and Femodene, and which is already reported to have paid out millions of dollars in litigation relating to these drugs in the US, has said that it would be making blood clot warnings more prominent on its packets as a result of the findings of the French study.

This comes after a review by the European Medicines Agency which found that the packaging of the pills should be updated to ensure that women are made aware of the risks of blood clots.