ORAL CONTRACEPTIVES are also called "birth control pills."
There are drugs that are used to prevent pregnancy.
This medication includes synthetic oestrogen and progesterone.
Effects on pregnancy of these hormones (normal mechanism)
The egg cell or ovum are produced by the ovaries and released into the fallopian tube.
Then, in the fallopian tube, this egg was fertilised by sperm.
After that, the egg travels to the uterus, where the endometrium (uterine lining) has expanded and is ready to accept a fertilised egg.
Estrogen cause thickening of endometrium.
Progesterone also causes thinking of endometrium and thinking of cervix which prevent sperms from passing through it.
When an egg doesn't become fertilised, the levels of the hormones progesterone and oestrogen start to decline, which results in menstruation.
There are two main type of contraceptives-
A. Combined pills-
It has estrogen and progesterone in it.
The estrogen prevents FSH from being secreted (through a negative feedback mechanism), which suppresses ovulation.
Progesterone prevents the release of LH, which prevents ovulation and results in no ovulation.
Progesterone also makes the cervix thicker.
Estrogen and progesterone change the endometrium in such a manner as to prevent implantation when they are kept at a constant level.
This is most effective method.
It has adverse effect like weight gain, nausea, vomiting etc.
B. Progesterone only pills (mini pills)
It only contains progesterone.
Progesterone prevents the release of LH, which prevents ovulation and results in no ovulation.
Progesterone also makes the cervix thicker.
Effectiveness is less than the combined pills.
Here is a mind map diagram illustrating the two main types of contraceptive pills: Combined Pills and Progesterone Only Pills (Mini Pills):
here's a summary of the requested oral contraceptives:
Classification | Example | Mechanism of Action | Uses | Side Effects |
Progestin Only | Norgestrel, Levonorgestrel | Inhibit ovulation, thicken cervical mucus, thin endometrium | Contraception, emergency contraception (Levonorgestrel) | Irregular bleeding, weight gain, depression, acne |
Antiprogestin | Mifepristone | Binds to progesterone receptors, blocking the action of progesterone | Emergency contraception, medical abortion | Heavy bleeding, nausea, headache, fatigue |
Note: Progestin-only contraceptives are often used in women who cannot use estrogen for various reasons.
Mifepristone is used in combination with a prostaglandin analog (like Misoprostol) for medical abortion.