Key Points: Contraceptive Methods

Natural Methods

• Rhythm method: Avoid intercourse on days 10–17 (fertile window around ovulation day 14). Effectiveness ~75%. Fails with irregular cycles.
• Coitus interruptus: Withdrawal before ejaculation. No devices. Low compliance.
• Lactational amenorrhea (LAM): High prolactin during exclusive breastfeeding suppresses GnRH → no LH/FSH → no ovulation. Effective for a maximum of 6 months. Requires exclusive breastfeeding.

Barrier Methods

• Male condom: Latex sheath over penis. Contraception + STD protection.
• Female condom: Polyurethane sheath in vagina. Also provides STD protection.
• Diaphragm / Cervical cap: Covers cervix. Contraception only — NO STD protection.
• Critical NEET point: ONLY condoms provide dual protection (contraception + STDs).

Intrauterine Devices

• Copper IUDs (Cu-T, Cu-7, Multiload 375): Non-hormonal. Cu2+ ions are spermicidal and increase uterine macrophage phagocytosis of sperm. ~99% effective.
• LNG-20 (hormonal IUD): Releases levonorgestrel. Thickens cervical mucus + makes endometrium inhospitable. ~99.8% effective.

Hormonal Methods

• Combined OC pills: Contain synthetic progestogen + estrogen. Suppress GnRH via negative feedback → no LH surge → no ovulation. ~99% effective. Steroidal.
• Saheli (centchroman): NON-STEROIDAL oral contraceptive. Developed by CDRI Lucknow. Taken once weekly (after loading phase). Centchroman = SERM → blocks estrogen receptors in uterus → prevents implantation (NOT ovulation). ~98% effective.
• Key distinction: OC pills prevent ovulation; Saheli prevents implantation.

Surgical Methods

• Vasectomy: Vas deferens cut and tied in males. Sperm production continues but sperm are reabsorbed. No sperm in ejaculate. ~99.9% effective. Essentially permanent.
• Tubectomy: Fallopian tubes cut and tied in females. Egg cannot reach uterus. ~99.9% effective. Essentially permanent.

Effectiveness Ranking (lowest to highest): Rhythm (~75%) < Condoms (~82–98%) < LAM (~98%) < Saheli (~98%) < OC pills (~99%) < Cu-T (~99%) < LNG-20 (~99.8%) < Vasectomy/Tubectomy (~99.9%)

Most Important NEET Facts:

1. Saheli = non-steroidal (centchroman) = CDRI Lucknow = once weekly = prevents implantation
2. Cu-T = non-hormonal = Cu2+ ions = spermicidal + phagocytosis
3. Only condoms = dual protection against both pregnancy and STDs
4. Vasectomy ≠ end of sperm production (sperm are still produced, just reabsorbed)