The cause of heavy menstrual bleeding is unknown, but a number of conditions may cause menorrhagia. Common causes include hormonal imbalance, uterine fibroids, Polyps, Dysfunction of the ovaries, Adenomyosis, Intrauterine device
(IUD),pregnancy complications like miscarriage, uterine cancer
, ovarian cancer
and cervical cancer
, Certain drugs, including anti-inflammatory medications and anticoagulants, a number of other medical conditions, like pelvic inflammatory disease
(PID), thyroid problems, endometriosis, and liver or kidney disease. It is difficult to say from your history as what is the cause, we can arrive at specific diagnosis only after clinical examination followed by few investigations. Specific treatment for menorrhagia is based on a number of factors like overall health and medical history, the cause and severity of the condition, tolerance for specific medications, procedures or therapies, effects of the condition on lifestyle and personal preference.