Contraceptive Effectiveness Reference
Summarized first-year pregnancy risk ranges aligned with CDC / WHO contraception efficacy teaching materials, distinguishing typical use (real adherence) versus perfect use.
| 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 |
Lactational amenorrhea methods, emergency contraception windows, sterilization reversal, hormonal interactions with enzyme-inducing meds, and pelvic inflammatory disease counselling all require clinician discussion — tables here cannot substitute.
Important usage notes & limitations
Reproductive timelines interact with contraception cessation, PCOS phenotype, transgender hormone therapy intensity, low body-fat athletic amenorrhea, and perimenopause. Hormonal contraception intentionally suppresses natural ovulatory signals until washout stabilization — calendar methods become meaningful only once cycles resume reliably.
See also: Pregnancy Due Date Calculator · Women's health calculators hub.