What does red spotting instead of period mean?

If it is during the: Point of your menstrual cycle when would expect to menstruate - it might be a light period. The main reason for light periods is change in hormone levels. Causes for what seems to be a light period can include: thyroid problems, eating disorders, excessive exercise, initial period, use of an intrauterine device, oral contraceptives, perimenopause ; implantation bleeding in early pregnancy.