If this occurs for a relatively short period of time, only 1-2 days, you can continue to observe again, because some people may have a normal menstrual flow after 3-4 days, which is caused by the incomplete atrophy of the corpus luteum in the woman’s body. If after 3-4 days, the blood is still pink, the first thing to do is to rule out pregnancy-related illnesses and do a urine test to see if you are pregnant. If it is pregnancy, it may also be caused by a lower level of hormones in the body that cannot maintain the endometrium, which in turn causes the endometrium to shed. There is also a condition to rule out the possibility of ectopic pregnancy, so if you keep having pink blood until it is time to have your period, and it is still like this for 5-6 days, it is best to go to the hospital for a chorionic gonadotropin test.