Obstetrics & GynaecologyContraceptionhigh-yield
Contraceptive methods compared
Mechanism, key contraindications and best-fit patient for every major contraceptive method in one comparison.
6 min read · updated 2026-08-24
The logic before the list
Every method blocks fertilisation at one of three points: stop ovulation (hormonal suppression of the axis), block the sperm (barrier or a hostile cervix/endometrium), or prevent implantation (copper toxicity, endometrial thinning). Fix the mechanism first and the contraindications fall out on their own — anything oestrogen-containing carries a thrombosis and oestrogen-dependent tumour risk, so those are the traps.
Method-by-method
| Method | Main mechanism | Key contraindications | Suits whom |
|---|---|---|---|
| Combined oral pill (COC) | Oestrogen + progestogen suppress FSH/LH → no ovulation; also thickens mucus, thins endometrium | Migraine with aura, smoker >35 y, VTE/thrombophilia, breast cancer, uncontrolled HTN, active liver disease, <6 wk postpartum/breastfeeding | Young, non-smoking woman wanting cycle control, less dysmenorrhoea, acne benefit |
| Progestogen-only pill (POP) | Thickens cervical mucus, thins endometrium; ovulation blocked only partially | Current breast cancer; needs strict same-time daily dosing | Breastfeeding mother, smoker >35 y, or anyone in whom oestrogen is barred |
| Copper IUCD (Cu-T 380A) | Copper ions are spermicidal + inflammatory endometrium → blocks fertilisation & implantation | Pelvic infection/PID, undiagnosed bleeding, distorted cavity, Wilson disease, pregnancy, copper allergy | Woman wanting long-acting, non-hormonal cover; also emergency contraception up to 5 days |
| LNG-IUS (hormonal IUD) | Local levonorgestrel thins endometrium, thickens mucus | Current breast cancer, pelvic infection, undiagnosed bleeding | Woman with menorrhagia (turns it into a treatment), oestrogen contraindicated |
| Implant (etonogestrel) | Progestogen suppresses ovulation for 3 y | Current breast cancer, undiagnosed bleeding | Wants highest efficacy, "fit-and-forget", poor pill compliance |
| Injectable (DMPA) | Progestogen suppresses ovulation, given 3-monthly | Current breast cancer; caution — reversible bone density loss, delayed return of fertility | Wants privacy/compliance-free cover, near completed family |
| Barrier (condom/diaphragm) | Mechanical block of sperm | Latex allergy (use polyurethane) | Anyone needing STI protection; new/multiple partners |
| Emergency contraception | LNG 1.5 mg or ulipristal delays ovulation; copper IUCD is most effective | Established pregnancy (it does not disrupt it) | After unprotected sex — LNG within 72 h, IUCD within 120 h |
The exam traps
- Copper IUCD is the most effective emergency method and also the only one that provides ongoing cover.
- DMPA is the method linked to reversible loss of bone mineral density and the longest delay in fertility return.
- COC in a migraine-with-aura patient sharply raises stroke risk — an absolute bar.
- Postpartum breastfeeding: avoid oestrogen; POP/implant/DMPA are safe.
Pearl: match mechanism to the contraindication — if oestrogen is dangerous (smoker >35, migraine with aura, VTE, breastfeeding), reach for a progestogen-only or copper method every time.
Sources
- DC Dutta's Textbook of Gynaecology, 8e
- Park's Textbook of Preventive and Social Medicine, 27e