There are many conditions that can lead to the symptoms that you speak of. The bottom line though, is that none of them are 'normal' God designed the perfect body and illness doesn't occur in a vaccum. Most western medical doctors treat the symptoms with drugs, or by yanking out organs, instead of looking for the root cause to disease.
Several things come to mind:
b6 and essensial fatty acids deficiency causes PMS.
Zinc deficiency causes delayed, irregular menses.
A need for Iron can cause heavy prolonged periods.
Vit K deficiency will cause overall increased bleeding.(long courses of antibiotics wipe out good gut bacteria and can cause k deficiency)High saturated fat diets need more vit k.
But my first thought was estrogen and it's effects on the body. We live in an age where we are bombarded with excessive amounts of estrogen. These high amounts WILL affect our periods, pms, fertility and more.
You are stating that high levels of estrogen, in the form of birth control pills, are having no effect on reducing her symptoms. It could be that estrogen is in fact the problem. Estrogen has a direct effect on increasing prolactin, which causes ovulation problems. estrogen causes fibriods, pms pain, excessive bleeding, prostate enlargement, and more.
Where do we get estrogen in our diets?
*Chlorine in our public water mimics estrogen: it has the same effect on us as estrogen. Chlorine also suppressees the immune system,alters cholesterol metabolism, Stops vit A from going out from the liver,destroys A, B, C and E, and omega 3, 6, and 9. Causes poor thyroid function, breast cancer,and colitis. Put a reverse osmosis filter on your tap.
*Estrogen is already in our public water supply from females who are taking the pill, this estrogen( in the urine) does not get filtered out of the public water supply.
*babies fed a soy based formula is equivalent to giving them 5 birth control pills a day. When those soy fed children get to puberty (and many have) they will have major problems with PMS, fertility, and even elevated female cancer rates.
* Dental sealants have a very high estrogen impact on our body with very little exposure.
*HMBP, in almost all sunscreens and lotions.Parabens are estrogenic. Use coconut oil in place of commerical lotions.
Mercola.com has an estrogen/paraben free sunscreen.
*PCB's and plastics
*BHT, the preservative put in processed foods (cereals, etc)
*DDT, Kepone, and Toxophane (pesticides used in agriculture)
*and genetically modified Soy, of which the USA has become the top manufacterer in the world. It is in almost EVERY processed food, in the form of soy casienate, soy protien, soy extract, soy lethicin, etc. It can be listed under natural flavorings as well.
* estrogens added to cattle (beef and dairy milk).
We've got to get away from all this estrogen!
Thyroid also impacts the reproductive system. I know you said she was tested, but most of the thyroid tests are ineffective at catching thyroid problems and many people are walking around undiagnosed. A better way to check for thyroid problems is to check basal body temp in the morning, upon waking but before rising.(look up online) Iodine helps normalize thyroid (150-225 mcgs a day) and you can check deficiency with a patch test on the skin. (look this up online)paint a 2 inch wide square of iodine on the shoulder and see how quickly it dissapears - it can tell you if you are deficient. Boron is another thing that helps normalize estrogen and testosterone. It can be bought in powder form at the pharmacy and mixed into water ( 1/2 t to a quart)drink daily 5 days a week, or you can get it in ionic form in a FULVIC ACID supplement (which I would highly reccomend anyway. )Fulvics also release chemical toxins and heavy metals and support immunity. Fulvics are filled with 60+ trace minerals, many of which are antibacterial.
Along with getting all estrogen out of her diet and environment, I would recommend B complex drops in liquid form (at walmart)2 drops twice a day under the tounge.Then immediately take the fulvic acid (it will help with uptake of all other supplements).
Grape seed extract strengthens connective tissue (the uterus is made of connective tissue)
Strengthens blood vessels, helps circulation, but it could cause more bleeding as it thins the blood a bit. Calendula and Artemesia could help.Look them up online.