Update on the Risk of Blood Clots following EU review (November 2013)
The benefits of combined hormonal contraceptives (CHCs) in pregnancy prevention are well established. It has also long been recognised that all CHCs are associated with a small increase in the risk of blood clots, compared with no use.
A European wide review, which concluded in November 2013, looked at all available evidence on the safety and efficacy of these medicines and confirmed that the balance of benefits and risks for CHCs remains positive in preventing unplanned pregnancies. The review confirmed our previous understanding of the risk of blood clots as being small and reinforced the importance of ensuring that clear and up-to-date information is provided to women and healthcare professionals.
It was recommended that the licensed product information for CHCs be updated to help women make informed decisions about their choice of contraception together with their healthcare professional. In addition, guidance documents (see below) were developed to provide more information to healthcare professionals and patients about the risk of blood clots with CHCs including which conditions increase the risk of a clot, the signs and symptoms of a blood clot and when patients need to tell their healthcare professional that they are using a CHC.
If you have been using your CHC without any problems there is no need to stop taking it on the basis of the review. If you have any concerns, you should discuss them with your contraceptive provider at your next routine appointment, but keep taking your CHC in the meantime. Remember that suddenly stopping a CHC may result in unintended pregnancy. For further information, please read the package leaflet that accompanies your combined hormonal contraceptive medicine or talk to your healthcare professional.
Further Information
The main conclusions of the review are outlined below and further information is available on the European Medicines Agency website.
Please find the Q&A document for women informing them of the conclusions of the review.
A letter sent to healthcare professionals informing them of the conclusions of the review can be accessed on the HPRA website.
Educational material for healthcare professionals and patients
As above, educational materials for prescribers and patients were developed to facilitate discussions between healthcare professionals and patients about the risk of blood clots with CHCs and these are available below:
Prescriber Checklist
Information Sheet for Women
Conclusions and recommendations of the review:
- The Europe-wide review looked at the benefits and risks of CHCs, particularly the risk of blood clots associated with these medicines. It confirmed that the benefits of CHCs outweigh the risk of blood clots, which has been known for many years and is very low.
- The risk of blood clots in the veins varies between CHCs, depending on the type of the hormone progestogen they contain, and ranges from 5 to 12 cases of blood clots per 10,000 women who use them for a year. This compares with 2 cases of blood clots in the veins each year per 10,000 women who are not using CHCs.
- The risk of blood clots in the veins varies between CHCs, depending on the type of progestogen they contain, and ranges from 5 to 12 cases of blood clots per 10,000 women who use them for a year (see table below). This compares with 2 cases of blood clots in the veins each year per 10,000 women who are not using CHCs.
Risk of developing a blood clot (VTE) in a year |
| Women not using a combined hormonal pill/patch/ring and are not pregnant | About 2 out of 10,000 women |
| Women using a CHC containing levonorgestrel, norethisterone or norgestimate | About 5-7 out of 10,000 women |
| Women using a CHC containing etonogestrel or norelgestromin | About 6-12 out of 10,000 women |
| Women using a CHC containing drospirenone, gestodene or desogestrel | About 9-12 out of 10,000 women |
| Women using a CHC containing chlormadinone, dienogest or nomegestrol | Not yet known* |
* Further studies are on-going or planned to collect sufficient data to estimate the risk for these products.
- Patients should discuss with their doctor or nurse what is the most appropriate type of contraception for them.
- When taking CHCs, patients should be alert for the signs and symptoms of blood clots, which may include severe pain or swelling in the legs, sudden unexplained breathlessness, rapid breathing or cough, chest pain, and weakness or numbness of the face, arm or leg. If you develop any of these signs and symptoms you should seek medical advice immediately.
- If you have been taking CHCs without any problem, there is no reason for you to stop taking them on the basis of this review. But it is important that you are aware of the risk of blood clots associated with these medicines, even though it is very low.
The most recent product information (Summaries of Product Characteristics [SmPCs] and package leaflets) for individual combined hormonal contraceptive products is available on our 'Find a Medicine' search page.