Combined hormonal contraceptives

Safety advisory - updated information about risk of blood clots

21 December 2016

Consumers and health professionals are advised that the TGA has completed a review of the risk of thromboembolic disorders (also known as blood clot disorders) in women taking a combined hormonal contraceptive (CHC) containing ethinyloestradiol and a progestogen. These medicines are also known as combined oral contraceptives.

As part of its review, the TGA sought advice from the Advisory Committee on the Safety of Medicines (ACSOM). The meeting statement from the relevant ACSOM meeting is available on the TGA website.

The advice included:

  • The risk of venous thromboembolism (also commonly known as a blood clot), such as deep vein thrombosis and pulmonary embolism, for women is generally rare – about two cases in every 10,000 women per year.
  • For women who are using one of the CHCs currently available in Australia, the risk of a blood clot is increased but is still rare.
  • The currently available data indicate that the increase in risk varies according to the progestogen included in the CHC (see table below).
  • The risk of arterial thromboembolism, such as stroke or heart attack, is also increased while using CHCs, but is even rarer and there is no evidence for differences between CHCs in the risk of arterial thromboembolism. The risk of arterial thromboembolism from using CHCs increases with age, smoking and obesity.
  • The Product Information (PI) and Consumer Medicines Information (CMI) documents for CHCs should be updated regarding blood clot risk to ensure clearer and more consistent information is provided across products.

The European Medicines Agency (EMA) also recently undertook a review of this issue and came to similar conclusions.

The sponsors of some CHCs have already incorporated updated information into their PIs and CMIs. The TGA is now working with other sponsors to update their PIs and CMIs.

Blood clot risk data

In its advice to the TGA, ACSOM agreed with the EMA Pharmacovigilance Risk Assessment Committee that, based on the currently available data, CHCs containing the same amount of oestradiol can be ranked by risk of developing a blood clot according to their progestogen component as follows:

Approximate risk of developing a blood clot in a year, per 10,000 women
Progestogen component of CHC Risk
levonorgestrel, norethisterone, norgestimate 5-7
etonogestrel, norelgestromin 6-12
drospirenone, gestodene, desogestrel, cyproterone* 9-12
chlormadinone, dienogest, nomegestrol Not yet known

* While cyproterone is indicated for the treatment of moderate to severe acne related to androgen sensitivity and/or hirsutism, it is known to have efficacy as a contraceptive. The risk of developing a blood clot associated with cyproterone use is considered to be 1.5 to 2 times higher than for CHCs containing levonorgestrel and may be similar to the risk with contraceptives containing gestodene, desogestrel or drospirenone.

The risk is likely to be increased for a woman if she has other risk factors for blood clots including:

  • is older than 35 years
  • smokes
  • has a body mass index > 30kg/m2
  • has an hereditary or acquired predisposition for blood clots, including activated protein C (APC)-resistance (such as Factor V Leiden)
  • has a personal and family history of blood clots
  • is immobilised (for example, following surgery or during long-haul air travel)
  • has any one of several other risk factors that increase the risk of developing a blood clot.

Information for consumers

If you take or are considering beginning to take a CHC, read the related CMI.

It is important to be aware of the potential risk of blood clot disorders associated with CHCs, but you should not be unduly alarmed.

This information is intended to help you and your health professionals make better informed choices about the use of CHCs.

To minimise the risk of blood clot disorders, CHCs should not be used by anyone who has or is at risk of developing blood clot disorders (see above under 'Blood clot risk data').

You are urged to discuss the benefits and risks of taking a CHC, or any other questions or concerns you have, with your health professional.

You should also talk to your health professional if you experience any of the signs or symptoms of blood clot disorders, including:

  • swelling, pain and/or redness in a limb
  • shortness of breath or difficulty breathing
  • faster than usual or irregular heartbeat
  • chest pain or discomfort, often worse when breathing in or coughing
  • dizziness
  • feeling sweaty
  • nausea
  • sudden numbness, weakness or loss of movement in the face, arm, or leg
  • sudden confusion, difficulty speaking, or difficulty understanding speech
  • sudden decrease, loss or blurring of vision
  • sudden trouble walking, loss of balance or lack of coordination.

Information for health professionals

If you are considering prescribing a CHC or are treating a patient who is taking a CHC, ensure that you are familiar with information provided in this web statement. In particular be aware of the contraindications and precautions relating to the risk of thromboembolic disorders associated with CHCs.

Educate patients regarding the signs and symptoms of thromboembolic disorders and instruct them to contact you if they experience aggravation, exacerbation or first appearance of any of the conditions/risk factors listed below. If any of the conditions appear for the first time during use, the CHC should be stopped immediately.

Contraindications relating to the risk of thromboembolic disorders are:

  • Presence or risk of venous thromboembolism (VTE):
    • Current VTE (on anticoagulants) or history of deep venous thrombosis or pulmonary embolism, or other thrombotic disorder.
    • Known hereditary or acquired predisposition for venous thromboembolism, such as APC-resistance (including Factor V Leiden), antithrombin III-deficiency, protein C deficiency, and protein S deficiency.
    • Major surgery with prolonged immobilisation.
    • A high risk of VTE due to the presence of multiple risk factors.
  • Presence or risk of arterial thromboembolism (ATE):
    • Current ATE or history of ATE (for example myocardial infarction or stroke) or prodromal condition (for example angina pectoris or transient ischaemic attack; transient ischaemic attack).
    • Known hereditary or acquired predisposition for ATE, such as hyperhomocysteinaemia and antiphospholipid-antibodies (for example anticardiolipin antibodies and lupus anticoagulant).
    • History of migraine with focal neurological symptoms.
    • A high risk of ATE due to multiple risk factors or to the presence of one serious risk factor such as:
      • diabetes mellitus with vascular symptoms
      • severe hypertension
      • severe dyslipoproteinaemia.

Reporting problems

Consumers and health professionals are encouraged to report problems with medicines or vaccines. Your report will contribute to the TGA's monitoring of these products.

The TGA cannot give advice about an individual's medical condition. You are strongly encouraged to talk with a health professional if you are concerned about a possible adverse event associated with a medicine or vaccine.