What Causes Heavy Bleeding During Menstruation?

My name is dipankar bor gohain and my wife is suffering from heavy bleeding during her mensuration periods for last 8 monts.This heavyBleeding ramains for 20 days.We have consulted reknowed gynocologist Dr Arun Madhav Baruah of Assam.He made some test and after seeing the test he has implmented Merina to stop her bleeding.But it did not worked and problem remain same.When we have apporched him for the second time he has done some blood test.
These reports says her hemoglobin perchantage is low followed by problem of K defficiency and less plate late count perchantage.Are these the causes of her heavy bleeding or any other reason.Kindly advise for necessary treatment