If you have had your period on the pill, you will not be pregnant. A woman’s menstrual flow is due to a decrease in the level of estrogen and progesterone in her body, and the endometrium loses hormonal protection and support, and shedding occurs, resulting in a menstrual flow. Pregnancy results in the production of the corpus luteum of pregnancy, which then secretes estrogen and progesterone, thus maintaining the endometrium and resulting in the absence of menstruation. If the patient has a period indicating that she is not pregnant, pay attention to the amount of menstruation, because a small number of women who are pregnant still have a small amount of bleeding, which is different from the amount of menstruation, less than the amount of menstruation and not as dark red in color as menstruation, if this is the case it is still necessary to check if they are pregnant.