CBSE · Class 12 · Biology · Reproductive HealthDiscuss the various categories of contraception used for birth control, giving examples of methods in each category along with their mode of action.

Introduction to Contraception\nAn ideal contraceptive should be user-friendly, easily available, effective, and have least or no side-effects. It should in no way interfere with the user's sexual drive, desire, and/or sexual act. Contraceptive methods are broadly classified into several categories based on their mechanism and application.

Categories of Contraceptive Methods

1. Natural / Traditional Methods

   • Principle: These methods work on the principle of avoiding chances of ovum and sperm meeting.
   • Periodic Abstinence: Couples avoid coitus from day 10 to 17 of the menstrual cycle when ovulation is expected.
   • Withdrawal or Coitus Interruptus: The male partner withdraws his penis from the vagina just before ejaculation so as to inseminate outside.
   • Lactational Amenorrhea: Based on the fact that ovulation does not occur during the period of intense lactation following parturition (effective up to 6 months).

2. Barrier Methods

   • Principle: In these methods, ovum and sperm are prevented from physically meeting with the help of barriers.
   • Condoms: Barriers made of thin rubber/latex sheath used to cover the penis in males or vagina and cervix in females (e.g., Nirodh). They also protect against STIs.
   • Diaphragms, Cervical Caps, and Vaults: Barrier made of rubber inserted into the female reproductive tract to cover the cervix during coitus.

3. Intra Uterine Devices (IUDs)

   • Principle: Inserted by expert doctors/nurses in the uterus through vagina. They increase phagocytosis of sperms within the uterus, suppress sperm motility, and reduce fertilizing capacity.
   • Non-medicated IUDs: e.g., Lippes loop.
   • Copper-releasing IUDs: e.g., CuT, Cu7, Multiload 375 (copper ions suppress sperm motility).
   • Hormone-releasing IUDs: e.g., Progestasert, LNG-20 (make the uterus unsuitable for implantation and cervix hostile to sperms).

4. Oral Contraceptive Pills (OCPs)

   • Principle: Small doses of either progestogens or progestogen-estrogen combinations used by females in the form of tablets.
   • Action: They inhibit ovulation and implantation as well as alter the quality of cervical mucus to prevent entry of sperms (e.g., Saheli).

5. Surgical Methods (Sterilization)

   • Principle: Terminal methods blocking gamete transport to prevent conception.
   • Vasectomy: A small part of the vas deferens is removed or tied up through a small incision on the scrotum in males.
   • Tubectomy: A small part of the fallopian tube is removed or tied up through a small incision in the abdomen or through vagina in females.