Dear An: Both FCL and An_6061 have given good input. If the "hormone pills" (I assume some form of synthetic progesterone) did not help, the search for the cause of the bleeding should be resumed.
There are two major reasons for very prolonged/heavy periods: hormonal and what I call "structural". "Structural" means when excessive bleeding is due to actual problems within the cavity or walls of the uterus. Some examples of this would include fibroids of the uterus, endometriosis of the muscular wall of the uterus ("adenomyosis"), infections of the lining of the uterus, polyps of the uterine lining, or even uterine cancer.
Hormonal causes are usually linked to missed or erratic ovulations. As you may know, in a normal cycle, estrogen is produced all month. Estrogen is responsible for building up the lining of your uterus so you have something to shed each month. In a normal cycle, progesterone production increases following ovulation. Progesterone "stabilizes" the uterine lining in preparation for a possible implantation of a new pregnancy. If you are not pregnant that month the levels of estrogen and progesterone fall, triggering the release of the uterine lining—your period. So, if you do not ovulate, the estrogen build up of the lining continues, but without the usual ovulation associated progesterone. Thus, the hormone levels don't decline, and the lining stays up inside the uterus—your missed/late period. Alternatively the lining can begin to shed under its own weight producing prolonged bleeding.
Another way inadequate progesterone production from missed ovulations can create too heavy a flow is as follows. Simply stated, if the uterine lining is like grass or lawn, estrogen is like the fertilizer (causes a thickening of the lining ), and progesterone is like the lawnmower (keeps the lining thin by three different mechanisms). This is why DepoProvera (high dose synthetic progesterone) brings about a thin lining, and why birth control pills (relatively progesterone dominant) bring about shorter, lighter periods. It is also why women who miss ovulations (no progesterone produced) are at a greater risk for too thick lining.
Causes for not ovulating are multifold: thyroid problems, pituitary problems, ovarian cysts, physical stressors (eg sudden increases in exercise, crash dieting), emotional stressors (problems with partners, finances,), increased body weight, anorexia, rotating shifts at work, etc.As FCL queried, if you are in your mid to late 40's there is an age related decrease in ovulations as one approaches peri-menopause.
Bottom line, please go back to your MD or consider seeing another GYN for more evaluations.
In Concern,
Jane