If there is a little bit of vaginal bleeding at the time of menstruation, it may be caused by pregnancy, and it is recommended to take a blood test to check the blood HCG or to do an early and early pregnancy test to rule out the possibility of pregnancy. Because normal menstruation is regular, and the amount, color and time of menstruation are the same as in the past, it is a normal physiological phenomenon. If the amount of menstruation suddenly reduced, in the clinical history of sexual intercourse, need to rule out the possibility of pregnancy, if not pregnant, may be caused by endocrine disorders, it is recommended to take oral progesterone for 3 days, usually stop the drug 3-7 days will come to menstruation, so do not be nervous.