Guidelines for prescribing combined oral contraceptives

EDITOR, - The clinical and scientific committee of the Faculty of Family Planning and Reproductive Health Care has noted a wide range of expert views on the recent publications on the combined oral contraceptive and venous thromboembolism[i-vi]and has circulated a position paper.[vii] The new studies confirm that low dose combined oral contraceptives carry an extremely low risk for healthy women.

The overall risk of venous thromboembolism for users of combined oral contraceptives containing gestodene and desogestrel is close to the previous estimate for all low dose combined oral contraceptives.[v] Combined oral contraceptives containing levonorgestrel and norethisterone seem to be associated with a lower risk of non-fatal venous thromboembolism than previously reported (table). 

Risk of non-fatal venous thromboembolism per 100,000 women per year

								Risk


Women not using combined oral contraceptives[v]			5-11
All women using low dose combined
oral contraceptives*						30
Women using combined oral contraceptives
containing desogestrel or gestodene**				30
Women using combined oral contraceptives
containing levonorgestrel or norethisterone			15
Pregnant women and women post partum				60



* According to latest British estimate before publication of recent
letter to all doctors from Committee on Safety of Medicines[x].
**Based on relative risk of twice the risk for women using
combined oral contraceptives containing levonorgestrel or norethisterone.

The data on myocardial infarction in women with no history of cardiovascular disease are reassuring. Lewis et al report no significant increase in the risk of myocardial infarction in users of pills containing gestodene or desogestrel compared with women not using the pill. The threefold increased risk of myocardial infarction previously reported in users of the combined oral contraceptive[viii] was still present among users of brands marketed earlier than pills containing desogestrel and gestodene. Smokers using brands marketed earlier had 11.1 times the risk of non-smoking women not using the pill (a significant difference), but the relative risk was 3.1 (not significant) m smokers using pills containing gestodene or desogestrel.[ix] We agree with Lewis et al that this one study, in which direct comparison of the products did not prove a significant difference, should be interpreted with extreme caution. We would welcome further comparative studies to confirm these findings.

The safety profile and observed high acceptability of products containing desogestrel or gestodene allow their continued use, subject to thorough, unbiased counselling in the context of all the recent studies and the letter from the Committee on Safety - of Medicines [x] The faculty is committed to developing evidence based guidelines, and until further data are available it endorses the guidelines given below

Prescribing guidelines

  • Prescribers should take a comprehensive personal and family history to exclude absolute contraindications to the use of combined oral contraceptives. These include a personal history of venous thromboembolism

  • Counselling should be thorough and unbiased and take into account all the recent studies and the letter from the Committee on Safety of Medicines[x]

  • Women with hereditary thrombophilia in a first degree relative should not be prescribed a combined oral contraceptive until thrombophilia has been excluded

    First time users of combined oral contraceptives

  • Prescribe a low dose combined oral contra ceptive containing no more than 35 mu g ethinyloestradiol and no more than 150 mu g levonorgestrel or I mg norethisterone, except when a higher dose is specifically indicated

  • Preparations containing desogestrel or gestodene may have an additional therapeutic role in women with specific medical conditions, including acne and hirsutism

    Established users of combined oral contraceptives containing gestodene or desogestrel

  • If risk factors for venous thromboembolism are present* the woman should be advised to change to another contraceptive method or to a preparation that does not contain gestodene or desogestrel, as appropriate

  • If after counselling the woman finds the risk of venous thromboembolism unacceptable then she should use a combined oral contraceptive that does not contain gestodene or desogestrel or another contraceptive method

  • The prescriber should respect the user's informed choice if she chooses to continue to take her current pill, even if only because she is satisfied with it

    Users of combined oral contraceptives that do Dot contain gestodene or decogestrel

  • A woman who has not tolerated combined oral contraceptives that do not contain gestodene or desogestrel, by virtue of experiencing persistent breakthrough bleeding or androgenic side effects, or for personal reasons, may be prescribed a combined oral contraceptive containing gestodene or desogestrel, having accepted the increased risk of venous thromboembolism 

    • *Risk factors for venous thromboembolism are hereditary thrombophilia; an acquired
predisposition, such as the presence of lupus anticoagulant or malignancy;
mechanical factors, such as immobility or trauma which may be acute or temporary,
or both); physiological factors, such as dehydration (which may be acute or
temporary, or both); obesity (defined as a body mass index of 30 or over); and
varicose veins (the data on the magnitude of risk attributable to varicose veins
are conflicting, but extensive varicosity is likely to be a risk factor) The
literature on the association of smoking with venous thromboembolic disease is
mostly negative


    A M MILLS (chair, clinical and scientific committee)
C L WILKINSON (secretary)
D R BROMHAM (committee member)
J ELIAS (committee member)
K FOTHERBY (committee member)
J GUILLEBAUD (committee member)
A KUBBA (committee member)
A WADE (committee member)


    Faculty of Family Planning and Reproductive Health Care
Royal College of Obstetricians and Gynaecologists
London NWI 4RG


    See also:


    

  • Third generation oral contraceptives and risk of venous thromboembolic
disorders: an international case-control study


  • Third generation oral contraceptives and risk of myocardial infarction: an
international case-control study


  • Third generation oral contraception and venous thromboembolism

    


    • 



    i. World Health Organisation Collaborative Study of Cardiovascular Disease and
Steroid Hormone Contraception. Venous thromboembolic disease and combined oral
contraceptives: results of international multicentre case-control study. Lancet
1995;346:1575-82.


    ii. World Health Organisation Collaborative Study of Cardiovascular Disease and
Steroid Hormone Contraception Effect of different progestagens in low oestrogen
oral contraceptives on venous thromboembolic disease. Lancet 1995, 346:1582-8.


    iii. Jack H, Jick S, Gurewich V, Wald Myers M, and Vasilakis C Risk of idiopathic
cardiovascular death and non-fatal venous thromboembolism in women using oral
contraceptives with differing progestagen components. Lancet 1995;346:1589-93.


    iv. Bloemenkamp KWM, Rosendaal FR, Helmerhorst FM, Buller HR, Vandenbroucke JP.
Enhancement by factor V Leiden mutation of risk of deep vein thrombosis
associated with oral contraceptives containing third-generation progestagen.
Lancet 1995;346:1593-6.


    v. Farmer RDT, Preston TD The risk of venous thromboembolism associated with low
oestrogen oral contraceptives Journal of Obstetrics and Gynaecology 1995;15
195-200


    vi. Spitzer WO, Lewis AL Heinemann LAJ, Thorogood M, MacRae KD on behalf of
Transnational Research Group on Oral Contraceptives and the Health of Young
Women. Third generation oral contraceptives and risk of venous thromboembolic
disorders: an international case-control study. BMJ 1996;312:83-8. (13 January).


    vii. Clinical and Scientific committee of the Faculty of Family Planning and
Reproductive Health Care of the Royal College of Obstetricians and Gynaecologists
Statement on combined oral contraceptive pills and risk of venous
thromboembolism. London FFPRHC, 1995


    viii. Vessey PM Recent advances in oral contraception - lessons learnt from
epidemiological studies British Journal of Family Planning 1984;10(1)(suppl 4)
4-10. ix. Lewis MA., Spitzer WO, Heinemann L AJ, MacRae KD, Bruppacher R,
Thorogood M on behalf of Transnational Research Group on Oral Contraceptives and
the Health of Young Women. Third generation oral contraceptives and risk of
myocardial infarction: an international case-control study. BMJ 1996,312:88-90.


    x. Committee on Safety of Medicines Combined oral contraceptives and
thromboembolism. London CSM, 1995