In normal early intrauterine pregnancy, once a woman becomes pregnant she will stop menstruating. When the sperm and egg unite to form a fertilized egg or form a trophoblast, the ovaries and trophoblast cells can continue to secrete estrogen and progesterone and maintain a certain level throughout the menstrual cycle, so there will not be a drop in estrogen and progesterone that causes the endometrial lining to peel off and bleed. However, a small number of pregnant women may show signs of pre-miscarriage, and a small amount of vaginal bleeding may occur at this time, but it is not a menstrual flow, and such patients need to undergo some treatment to preserve the pregnancy. If you stop menstruating after pregnancy, and if you still have vaginal bleeding after pregnancy, you should promptly consult an obstetrics and gynecology department to rule out other causes of bleeding, such as ectopic pregnancy and pre-eclampsia.