Contraceptive Effectiveness Reference
| Method | Typical‑use preg. per year (~) | Perfect‑use preg. per year (~) | Notes |
|---|---|---|---|
| Implant | 0.05% | 0.05% | Progestogen implants |
| IUD hormonal (LNG) | ~0.4–0.5% | 0.2–0.4% | Formulation-dependent |
| IUD copper | ~0.8% | <0.6% | Paraguard-class summaries |
| Injection (DMPA) | 4% | 0.2% | Booster punctuality drives typical-use risk |
| Combined pill/patch/ring | 7% | ~0.3% | Adherence dominates |
| Progestogen-only pill | 7–9% | ~0.3% | Narrow dosing windows |
| Internal condom | 21% | ~5% | Mechanical skill / slippage |
| External condom | 13% | ~2% | STI risk reduction synergy |
| Withdrawal | 20% | ~4% | Highly user-dependent pre-ejaculation variability |
| Fertility-awareness methods | 12–24% | ~1–5% | Protocol adherence + training quality |