Cue Column | Notes Column

Rhythm method mechanism | Avoid intercourse during fertile window — days 10–17 of menstrual cycle. Effectiveness: ~75%. Fails with irregular cycles.

Coitus interruptus | Male withdraws before ejaculation. Lowest compliance, low effectiveness. No devices needed.

LAM mechanism | Intensive breastfeeding → high prolactin → suppresses GnRH → no LH/FSH → no ovulation. Effective up to 6 months only if exclusive breastfeeding.

Barrier methods — STD protection | Only condoms $\frac{male}{female}$ protect against STDs. Diaphragm and cervical cap cover cervix only — no STD protection.

Cu-T mechanism | Cu2+ ions: spermicidal + increase phagocytosis of sperm by uterine macrophages. Also creates inflammatory environment inhibiting implantation. NON-HORMONAL.

LNG-20 mechanism | Releases levonorgestrel (progestogen): thickens cervical mucus + makes endometrium inhospitable. HORMONAL IUD.

Combined OC pills | Synthetic progestogen + estrogen → negative feedback on hypothalamus-pituitary → suppresses GnRH → no LH surge → no ovulation. Steroidal.

Saheli | Centchroman (SERM) → blocks estrogen receptors in uterus → prevents implantation. NON-STEROIDAL. Once weekly (after loading). CDRI Lucknow.

Vasectomy | Vas deferens cut + tied. Sperm still produced but reabsorbed. No sperm in ejaculate. Essentially permanent.

Tubectomy | Fallopian tubes cut + tied. Egg cannot travel to uterus. Essentially permanent.

Summary

Key hierarchy: Natural < Barrier < IUD < Hormonal < Surgical in effectiveness. Only condoms prevent STDs. Cu-T = non-hormonal (Cu2+ ions). LNG-20 = hormonal IUD. Saheli = non-steroidal oral (unique). Vasectomy = male surgical; Tubectomy = female surgical. Prolactin is the LAM hormone.