My menstrual cycle is 21 days but lately i discovered that from day 3-4 are always scanty and sometimes it will not flow up to four days, pls what could be the cause and remedy. can stress cause such a thing?

Normal menstrual cycles can take anywhere from 19 days to 30 days in cycle, and can result in heavy, medium or scant flow. These factors can be affected by stress, lack of sleep, weight gain/loss, new exercise regimen, drugs/alcohol, and many more factors. typically, when a person resumes their healthy lifestyle, their menstrual cycle goes back to normal.