The contraceptive pill taken once a month is called long-acting oral contraceptive pill, which is a large dose of progestin that can be absorbed into the fat in the body after eating and slowly released may play a contraceptive role, inhibit ovulation or make the cervical viscosity increase, which is not conducive to the passage of sperm, and can also inhibit the development of the endometrium, making the endometrium thinner and less likely to get pregnant. However, because of the high dose of the drug and its side effects, it is rarely used nowadays. If you want to use contraception, it is best to take short-acting oral contraceptives, which are safer and have a very high contraceptive success rate.