On the first day of menstruation, it is normal for menstrual blood to be pale in color, probably because the endometrial lining is less exfoliated and mixed in the leucorrhoea to appear diluted. During this period, women should pay attention to proper rest, keep warm and avoid getting cold. Generally, on the 2nd to 3rd day of menstruation, with the increase of endometrial exfoliation and smooth pelvic blood circulation, the color of menstrual blood will change from light to dark red, which is normal. If the menstrual blood is light in color and pink during the entire menstrual period, it is possible that the woman has anemia. In this case, it is also necessary to go to the hospital in time to do gynecological ultrasound and sex hormone and blood test, and according to the different reasons, use the corresponding drugs for treatment, so as not to affect the health of women.