Such studies highlight the need for further research into the influence of hormonal contraception, including the progestogen-only pill on women’s psychological health. Mechanism of action. The mechanism of action of progestogen-only contraceptives depends on the progestogen activity and dose.
While the "mini-pill" is more effective than certain other methods of birth control (such as condoms, cervical cap, diaphragm), it is less effective than combination hormone (estrogen and progestin) birth control because it does not consistently prevent ovulation. It is usually used by women who cannot take estrogen. To reduce the risk of pregnancy, it is very important to take this medication exactly as prescribed.