What is the significane of progesterone-estrogen combination as a contraceptive measure ?

Explanation

Progestogens or progestogen-estrogen combinations play an important role in contraception. They are used in the form of tablets or pills. They inhibit ovualation and hence implantation.
The are also used by females as injections or implants under the skin. Their mode of action is similar to that of pills but their effective periods are longer.