Makindo Medical Notes

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

• BNF: Combined hormonal contraceptives
• Faculty of Sexual & Reproductive Healthcare (FSRH) UKMEC guidance