Q.Describe the various methods of birth control to avoid pregnancy.

Step 1. Temporary methods avoid fertilization without permanently altering fertility. These include the natural/safe-period (rhythm) method and coitus interruptus (withdrawal), both with high failure rates; lactational amenorrhoea, relying on suppressed ovulation during intense breastfeeding; chemical spermicides (foams, jellies, creams); and mechanical/barrier methods — the condom (male), diaphragm/cervical cap/vault (female), and intra-uterine devices (the Lippes loop, copper-releasing Cu-T/Cu-7/Multiload, and hormone-releasing LNG-20/Progestasert).

Step 2. Physiological (oral) devices — the pill, containing progesterone and estrogen — inhibit ovulation and thicken cervical mucus against sperm; 'Saheli' is a government-sponsored non-steroidal weekly pill. Subdermal hormonal implants act similarly but protect for 3–4 years. …

• Listing MTP as a 'birth control' method in the same sense as contraceptives, when it terminates an existing pregnancy rather than preventing fertilizatio …