Synopsis
Prescribe the combined pill, patch or vaginal ring safely by applying UKMEC, measuring blood pressure, explaining thrombosis risk and using clear starting and review rules.
- Combined hormonal contraception includes the combined oral pill, transdermal patch and vaginal ring; all contain oestrogen plus progestogen and share major vascular eligibility considerations.
- Measure blood pressure and record BMI before starting. A pelvic examination, cervical screening, thrombophilia screen and routine blood tests are not prerequisites for an otherwise uncomplicated prescription.
- Ask specifically about migraine aura, smoking and age, VTE or thrombophilia, hypertension, cardiovascular disease, breast cancer, liver disease, postpartum state, surgery and interacting medicines.
- UKMEC category 4 examples for CHC include migraine with aura and blood pressure at or above 160/100 mmHg; do not prescribe while arranging confirmation or safer alternatives.
- A preparation containing no more than 30 micrograms ethinylestradiol with levonorgestrel or norethisterone is a reasonable initial oral option when no competing preference exists because VTE risk is comparatively lower.
- Standard 21/7 use is not physiologically necessary. Tailored regimens may use fewer or no hormone-free intervals, but any break must not exceed seven days and product-specific instructions matter.
- Starting on days 1–5 of a natural cycle gives immediate protection; at other times quick-start if pregnancy can reasonably be excluded and use condoms or abstain for seven days.
- Review blood pressure, adherence, new migraine or vascular symptoms, smoking, medicines and patient acceptability; routine short prescriptions should not create avoidable access gaps.
Key red flags
Current migraine with aura, previous venous thromboembolism, known thrombophilia, major vascular disease or severe hypertension can make oestrogen exposure an unacceptable risk.
A new severe headache, focal neurological symptom, chest symptom or unilateral leg swelling during CHC use requires urgent assessment rather than a routine contraceptive review.
Major surgery with anticipated prolonged immobility requires advance method planning because CHC compounds perioperative venous thromboembolism risk.
Pregnancy symptoms after missed pills, an extended hormone-free interval, vomiting, diarrhoea or an interacting medicine require prompt pregnancy-risk and emergency-contraception assessment.
Investigation priorities
Identify hypertension before oestrogen exposure and at clinically appropriate follow-up.
Management branches
A patient prefers a combined pill, patch or ring.
- Measure blood pressure and BMI and take a focused history of aura, smoking, thrombosis, vascular disease, postpartum status, breast or liver disease, surgery and medicines.
- Apply current UKMEC, exclude category 4 methods and use expert judgement or a safer alternative for category 3 or important combined risk factors.
- Agree the formulation and route, explain absolute benefits and harms, and document the eligibility information supporting the decision.