Synopsis
Prescribe combined pills, patches and rings safely by applying UKMEC 2025, formulation-specific use and interaction rules while supporting tailored regimens and urgent risk recognition.
- CHC includes combined oral pills, transdermal patches and vaginal rings; changing route does not avoid oestrogen-related VTE, stroke or migraine-aura restrictions.
- Current migraine with aura is UKMEC 4; aura at least five years in the past is category 3. Smoking from age 35 is category 3 below 15 cigarettes daily and category 4 at 15 or more.
- Adequately controlled hypertension or blood pressure 140–159/90–99 mmHg is UKMEC 3 for CHC; blood pressure at least 160 systolic or 100 diastolic, or vascular disease, is category 4.
Key red flags
New migraine aura is current aura and makes every CHC route UKMEC 4 even if previous headaches were labelled migraine without aura.
Chest pain, hypoxia, haemoptysis, unilateral leg swelling or syncope requires urgent VTE assessment rather than an annual pill review.
Focal weakness, speech disturbance, persistent visual deficit or sudden severe headache needs emergency neurological assessment.
Blood pressure at least 160/100 mmHg makes CHC UKMEC 4; repeat accurate measurement must not become a reason to ignore severe symptoms.
Breastfeeding makes CHC UKMEC 4 before six weeks, category 2 from six weeks to under six months, and category 1 from six months on that factor alone; postpartum VTE factors must also be assessed.
A new enzyme inducer can reduce contraceptive efficacy, while oestrogen can lower lamotrigine concentrations and destabilise seizure control.
Unilateral swelling or pain, unexplained breathlessness, pleuritic pain, haemoptysis or collapse suggests DVT or pulmonary embolism.
Focal deficit, speech or visual disturbance, severe sudden headache or cardiac chest pain requires emergency assessment.
Fully reversible focal visual, sensory or speech symptoms preceding headache differ from nonspecific blur and change CHC eligibility.
Enzyme induction, vomiting, severe diarrhoea or missed use near a hormone-free interval can permit ovulation and trigger emergency-contraception assessment.
Investigation priorities
Identify category 3 or 4 hypertension before initiation and during continuing use.
Management branches
An eligible person requests a combined pill, patch or ring.
- Check blood pressure, smoking, migraine aura, BMI, VTE and arterial history, postpartum or breastfeeding status, liver and breast disease and current medicines.
- Discuss effectiveness, LARC alternatives, VTE risk, bleeding, hormone-free symptoms and whether standard, shortened, extended or continuous use best fits the selected formulation.