I have been in overal  l for last 3 months . This month after i completed the 21 days pack bleeding ( period) started on the 3 rd day after i completed. But it was very light.today is 4 th day of my period . The three days flow was very light n it looks somewhat brownish today(4th day) . I did a trans vaginal scan on 2 nd day of period as suggested by doctor n it was all good .what is the reason for light bleeding ??