1. Delaying ovulation.

2. Inhibiting fertilization.

3. Preventing implantation of the fertilized egg.

4. Interrupting an early pregnancy.

 

2. Inhibiting fertilization.

Reference

Shaw Chapter Birth Control Topic Post coital contraception

Test book of Obstetrics 4^th Edition D.C.Dutta 588

Reader

Repeat

Shaw

Emergency Contraception or Post Coital Contraception is indicated in

1.        Unprotected Intercourse

2.        Condom Rupture

3.        Missed Pill

4.        Sexual Assault

5.        Rape

6.        First time intercourse [(according to Dutta) is known to be ALWAYS Unplanned!! J]

Methods Used are

1.        Morning after Pill

a.        Endometrium Unfavourable

b.        Interferes with the function of Corpus Luteum and Luteolysis

c.        Increased Tubal Peristalsis

d.       Delay of Ovulation

2.        Yuzpe Method

3.        IUCD

a.        Prevents Implantation

4.        Anti Progesterone(Mifepristone), on the 27^th day of the cycle, irrespective of the day of intercourse

a.        It does not prevent Fertilisation, but acts by blocking the action of Progesterone on Endometrium

5.        Danazol

6.        Interception

a.        Zygote is Formed, but prevented from Implantation or Organogenesis

1. Delaying ovulation is the mechanism of Pills.

2. No method acts by Inhibiting fertilization.

3. Preventing implantation of the fertilized egg is by IUCD.

4. Interrupting an early pregnancy is by RU 486.

The Answer is very clear. For those who may think that the Answer is 4, please note that 3 and 4 are essentially the same process and RU 486 as well as IUCDS do both

Take a note of Another drug Epostane that prevents Progesterone Synthesis