Thanks for choosing HCM,
Changes in body weight,hormonal
imbalances,cysts in ovaries,mental illness like stress
,vigorous dieting,change in diet,climate are the general common conditions for delayed periods.
these can be ruled out with proper clinical examinations as well as health tests.
other abnormal reasons like fibroids etc. are considered taking age and clinical signs into consideration.
bleeding for about 3 wks may be due to hormonal variations,better get those levels checked.
if age , marital status,gynaec history is provided i could give you a specific reason.
hope i answered your queries
feel free to contact me for further queries