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Combined hormonal contraception

How does combined hormonal contraception (CHC) work?

  • Women can be informed that the bleed experienced during the hormone-free interval or placebo week of pill taking is due to withdrawal of hormones rather than a menstrual bleed
  • Health professionals may wish to advise women about the use of extended or continuous regimens of CHC but should be aware that such use is off licence

CHC efficacy

  • Women can be informed that the efficacy of all CHCs is generally similar

Initial assessments for CHC

  • Health professionals should take a detailed history from women requesting CHC and should recheck the history at least annually. The history should include medical conditions such as migraine, drug use, family medical history, and lifestyle factors such as smoking
  • A blood pressure recording, and body mass index (BMI) should be documented for all women prior to first prescription of CHC

Drug interactions

  • Additional contraceptive precautions are not required when antibiotics that do not induce enzymes are used in conjunction with CHCs
  • Women who do not wish to change from a combined method while on short-term treatment with an enzyme-inducing drug (and for 28 days after stopping treatment) may opt to continue using a combined oral contraceptive (COC) containing at least 30 µg ethinylestradiol (EE), the patch or ring along with additional contraception. An extended or tricycling regimen should be used and the hormone-free interval shortened to 4 days. Additional contraception should be continued for 28 days after stopping the enzyme-inducing drug
  • With the exception of the very potent enzyme inducers rifampicin and rifabutin, women who are taking an enzyme-inducing drug and who do not wish to change from COC or use additional precautions may increase the dose of COC to at least 50 µg EE (maximum 70 µg EE) and use an extended or tricycling regimen with a pill-free interval of 4 days
  • Women taking lamotrigine (except in combination with sodium valproate) should be advised that due to the risk of reduced seizure control whilst on CHC, and the potential for toxicity in the CHC-free week, the risks of using CHC may outweigh the benefits
  • Women should be advised that ulipristal acetate (UPA) has the potential to reduce the efficacy of hormonal contraception. Additional precautions are advised for 14 days after taking UPA (9 days if using or starting the progestogen-only pill, 16 days for the estradiol valerate/dienogest pill) (outside product licence)

Risks, non-contraceptive health benefits and side effects

  • Health professionals should be aware that compared to non-users, the risk of venous thromboembolism (VTE) with use of CHC is approximately doubled but that the absolute risk is still very low
  • Health professionals prescribing CHCs should be guided by the individual's own personal preference, risk of VTE, any contraindications, possible non-contraceptive benefits and experience with other contraceptive formulations
  • A personal history of VTE or a known thrombogenic mutation are conditions that represent an unacceptable health risk if CHC is used
  • For women with a family history of VTE, a negative thrombophilia screen does not necessarily exclude all thrombogenic mutations
  • A thrombophilia screen is not recommended routinely before prescribing CHC
  • Use of CHC in women aged ≥35 years who smoke is not recommended
  • Health professionals should be aware that there may be a very small increase in the absolute risk of ischaemic stroke associated with CHC use
  • The risks of using CHC in women with properly taken blood pressure (BP) which is consistently elevated generally outweigh the advantages. Systolic BP ≥160 mmHg or diastolic BP ≥95 mmHg is a condition that represents an unacceptable health risk if CHC is used
  • The risk of using CHC in women with a BMI ≥35kg/m2 usually outweighs the benefits
  • Migraine with aura is a condition for which the use of CHC presents an unacceptable health risk
  • Health professionals should be aware that:
    • any risk of breast cancer associated with CHC use is likely to be small, and will reduce with time after stopping
    • CHC use may be associated with a small increase in the risk of cervical cancer which is related to duration of use
  • Health professionals should check that women coming for CHC are up to date with cervical cytology screening in accordance with screening recommendations
  • Women can be advised that CHC use does not appear to have a negative effect on overall mortality
  • Use of COC is associated with a reduced risk of ovarian and endometrial cancer that continues for several decades after stopping
  • Health professionals should be aware that:
    • CHC may help to improve acne
    • COC use is associated with a reduction in the risk of colorectal cancer and this may also apply to other CHCs
      that use of CHC may help to reduce menstrual pain and bleeding
  • Before starting CHC women should be advised about expected bleeding patterns both initially and in the longer term
  • Women can be advised that:
    • CHC may reduce menopausal symptoms
    • CHC may be associated with mood changes but there is no evidence that it causes depression
    • the current evidence does not support a causal association between CHC and weight gain

CHC whilst travelling or at high altitude

  • Women taking CHC should be advised about reducing periods of immobility during flights over 3 hours
  • Women trekking to altitudes of >4500 m for periods of more than 1 week may be advised to consider switching to an alternative method

full guidelines available from…
Faculty of Sexual & Reproductive Healthcare

FFPRHC guidance: Combined hormonal contraception. October 2011
First included: October 2011.