What are birth control pills?

Patient's question:

Please elaborate on that

Doctor's answer:

This type of multiphasic oral contraceptive is primarily designed to have lower doses of progestogen in the pills, which is intended to reduce the side effects of the contraceptive and make it more consistent with the progestogen levels during the menstrual cycle. Among them, those that divide the pills taken per cycle into two dosages are called biphasic pills, while those with three dosages are called triphasic pills.
The dosing sequence for multiphasic pills is usually carefully indicated on the packaging. Domestic triphasic pills are taken starting from the first day of menstruation, with one pill taken each day according to the marked sequence, for a total of 21 days. The second cycle begins on the third day of menstruation and is taken continuously for 21 days.