Oral cotraceptive pills are tablets that prevents conception. Perhaps its the most accepted contraceptive method in developing countries. Its principle function is to prevent conception and it doesn't give any protection against HIV and other STD's.
Oral Contraceptive Pills (OCP) are mainly two types.
1. Combiled OCP.
2. Progesteron OR Estrogen only Pills.
The mechanism of action of OCP is very simple. We know that female Menstrual cycle is devided into three phases.
1. Proliferative phase : Here estrogen is secreted by Ovary , which causes uterine endrometrial growth. After this phase there is sudden withdrwal af estrogen which causes Ovulation ( It is the fall of mature ovum into Peritoneal Cavity , which ultimately comes into the uterine tube and finally in uterus ).
2. Secretory phase : Here both Progesterone and Estrogen Causes more and more growth if endometrium and increase secretion by the uterine glands.
3. The Menstrual phase : Here sudden Withdrawal of Progesterone cause increase uterine contraction and shedding out of uterine endometrium with mature Ovum , which is visible as bleeding.
Now, OCP maintains a steady concentration of estrogen and progesterone into the body. Though , Ovulation occur due to sudden withdrawal of estrogen and OCP maintains estrogen level , so , there is no ovulation in the body. And , there is menstruation due to sudden withdrawal of progesterone , because , OCP intake should be stopped after 21 days. After this , the women will take 7 Iron tablets , and by this period there is sudden withdrwal of progesterone in the body. So , there is menstruation but without any ovulation.
Now, though there is no ovulation so , so Sperms inters into the vagina and uterus they can not find any mature ovum in female genital tract. So , there is no fertilization in the body. So, that women will not conceve .
By this way OCP maintains Contraception into the body.
