How effective is long-term short-acting birth control from the first day?

Patient's question:

First time using long-term short-acting birth control pills, not given how many days to take before it becomes effective, and also starting each month how many days to take before it becomes effective

Doctor's answer:

Hello, the effective time of short-term contraceptive medication is within 72 hours. As long as it is within this period, it is still effective, but there is still a possibility of accidental pregnancy. It is recommended to use an intrauterine device for contraception or to use condoms. In fact, in general, any form of contraception can cause certain damage to the patient. Therefore, patients should pay attention to their diet. Contraceptive patients should pay attention to their self-care, such as maintaining a balanced diet and avoiding cold, spicy, and irritating foods.