A little light blood in the menstrual period may be caused by pregnancy or endocrine disorders. When the menstrual period does not come normally, just a little light blood, if there is a recent history of sexual intercourse, combined with lower back and abdominal pain, can not be ruled out that the pregnancy is a case of miscarriage with preeclampsia. However, this situation may not be a manifestation of pregnancy, because menstruation is due to cyclical changes in the level of sex hormones in the female body, so that the endometrium is shed, discharged into the vagina and formed, if there is endocrine disorders resulting in changes in sex hormones, its regulatory role changes will make the period, the amount of menstruation is abnormal. If the entire menstrual period is light blood suggests that the menstrual flow is too small. Patients can go to the hospital to improve the sex hormone test, HCG test, to rule out the possibility of pregnancy. If the possibility of pregnancy is ruled out and there is no organic disease, pay attention to relaxing mood, regular life, adjusting diet, preventing cold and keeping warm.