Combined Oral contraceptive pill (COCP) 💊
Related Subjects:
| Management of Unprotected Sex and Emergency Contraception (EC)
| Contraception request/advice
| Combined Oral contraceptive pill (COCP)
The Combined Oral Contraceptive Pill (COCP) contains both oestrogen and progestogen.
⚠️ Increased risk of venous thromboembolism (VTE) — particularly in women over 35 who smoke, those with obesity, or with clotting disorders.
Always assess cardiovascular and thrombotic risk before prescribing.
📖 About
- Contains synthetic oestrogen (usually ethinylestradiol) + progestogen.
- Effectiveness:
- Perfect use: <1% failure rate/year.
- Typical use: ~9% failure rate/year (due to missed pills, interactions, GI upset).
⚙️ Mechanism of Action
- Main effect: Inhibits ovulation by suppressing FSH and LH surge.
- Thickens cervical mucus → hinders sperm penetration.
- Alters endometrium → reduces implantation likelihood.
✅ Benefits
- Highly effective reversible contraception.
- Regulates cycles, reduces dysmenorrhoea and menorrhagia.
- Reduces iron-deficiency anaemia risk (lighter periods).
- Improves acne and seborrhoea.
- Lowers risk of endometrial and ovarian cancer.
- Useful in PCOS, endometriosis, PMS.
- Protects against benign breast disease and functional ovarian cysts.
⚠️ Risks
- Thromboembolism (VTE, arterial thrombosis in high-risk women).
- ↑ Cardiovascular risk with smoking ≥35 yrs, obesity, hypertension, diabetes, dyslipidaemia.
- Slight ↑ breast cancer risk during use (returns to baseline ~10 years after stopping).
- ↑ risk of cervical cancer with long-term use (>10 yrs).
- Possible: weight change, nausea, breast tenderness, mood changes, reduced libido.
- Rare: hepatic adenomas, gallstones, raised BP.
🚫 Contraindications (UKMEC 4: absolute)
- Current breast cancer.
- VTE, stroke, TIA, ischaemic heart disease.
- Migraine with aura.
- Uncontrolled hypertension (≥160/100 mmHg) or hypertensive retinopathy.
- Major surgery with prolonged immobilisation (stop ≥4 weeks before).
- Known thrombogenic mutations (e.g., factor V Leiden, prothrombin mutation, protein C/S/antithrombin deficiency).
- Hepatocellular carcinoma, severe liver disease.
⚠️ Cautions (UKMEC 3: usually avoid)
- Age >35 and smoking ≥15/day.
- Controlled hypertension or cardiovascular risk factors.
- Past breast cancer (after 5 yrs disease-free).
- Postpartum <6 weeks if breastfeeding, <3 weeks if not breastfeeding with VTE risk factors.
- Systemic lupus erythematosus with antiphospholipid antibodies.
📋 Advice & Monitoring
- Baseline: BP, BMI, full medical & family history.
- Annual review: BP, BMI, new risk factors.
- Missed pills:
- 1 pill missed: take ASAP, continue as usual (may mean 2 in 1 day).
- ≥2 missed: take last pill missed ASAP, use condoms for 7 days. If pills missed in week 1 and UPSI occurred, emergency contraception may be needed.
- Drug interactions:
- Enzyme inducers (rifampicin, rifabutin, carbamazepine, phenytoin, St John’s Wort) ↓ efficacy.
- Broad-spectrum antibiotics do not reduce efficacy (unless vomiting/diarrhoea occurs).
📚 References
