The combined oral contraceptive is the most effective form of birth control available to women today. Its chief mechanism of action is the prevention of ovulation. Combined oral contraceptives are therefore also sometimes called ovulation inhibitors.

Inhibition of ovulation

After taking a combined oral contraceptive pill the sex hormones contained in the pill are carried by the bloodstream to the hypothalamus and the pituitary.

The pituitary reduces the production of FSH (follicle stimulating hormone). This suppresses the growth of the follicles and the production of estrogen by the body. As a result of the constant estrogen levels produced by the combined oral contraceptive the pituitary does not receive the signal to secrete large amounts of LH, the hormone which triggers ovulation in the natural menstrual cycle, around the middle of the cycle. Ovulation is therefore prevented. If no egg is released, you cannot become pregnant.

Other contraceptive actions of the combined oral contraceptive

The COC has two additional contraceptive effects.

It suppresses the thickening of the uterine lining and thus makes implantation of an egg in the uterus impossible.

In addition, the combined oral contraceptive causes the plug of mucus in the neck of the womb to retain its thick, sticky consistency which makes it impossible for sperm to penetrate. The cervical os and the neck of the womb remain closed.

The combined pill also provides contraceptive protection during the one-week tablet-free interval.

The combined oral contraceptive and sexually transmitted diseases

The combined oral contraceptive does not provide protection against HIV or other sexually transmitted diseases.

If you want to have sex with someone you do not know well you should use a condom.