Combined Hormonal Contraceptive Use

This guideline says little that is new, but updates the existing guidance with details from the recent guidelines on emergency contraception and missed pills. Combined Hormonal Contraception (CHC) includes the vaginal ring and patches. I have summarised some of the things I think are crucial, or found useful.

On initiating CHC

Take a thorough history (including migraine / medication use / FHx / lifestyle factors and CV risk factors – eg smoking, lipids, weight, hypertension, thrombophilia). Take their blood pressure and BMI.

Reasons for not starting CHC

There are lots of contra-indications. The most common for us are a BMI ≥ 35 (risks generally outweigh benefits), aged over 35 and is a smoker (or has been a smoker in the last year) or if they have migraine with aura. Further explanations and other contra-indications can be found in the UKMEC criteria. This is a fantastic resource if in doubt about any contraceptive use. It also defines ‘aura’, which can be very helpful if in doubt (eg flashing lights does not count as aura).

Starting routine

If a woman can have unpredictably short cycles, then she should start the pill on d1, or use additional precautions for 7d, as her date of ovulation could be unpredictable.


At 3m, then at least annually. BP and a history review should be done at every visit.

Extended Use Regimes

Women can be advised that they can use the pill in ‘extended regimes’, though this is off-license. They can either use it for 3m, then have a 4 to 7 day Pill Free Interval (PFI), or they can use it continuously until they have 3 to 4 days of break through bleeding and then have a 4 to 7 day PFI, or they can use it for 21 days, but just have a 4 day PFI. Some women may prefer these options to reduce bleeds, or side-effects.

Switching from one form of CHC to another

Women start the new CHC on the day after stopping the old form, with no PFI and no need for additional precautions (this is new advice as old BNF advice was to use additional precautions if changing the progesterone in the pill).

Antibiotics and the pill

Remember that with most antibiotics we now use (except for the unusual TB ones), women DO NOT need to use additional precautions, unless they vomit, have diarrhoea or miss a pill.

Travelling at altitude

If women are travelling above 4500m for more than a week, they should consider alternative contraception as they are at higher VTE risk.

Rings and Patches

There is quite a lot in this guideline about using rings and patches, but as we still don’t use them very much, I won’t go into that here. It is a good place to look if you have a query about their use though.

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