Too much estrogen compared to progesterone.
I am posting this due to seeing that so many seem to have been told that "we don't know what endometriosis really is."
Cycling means going through ongoing changes. And to be healthy, those changes should be in a specific pattern. So much estrogen compared to progesterone - and in the cycle that is in a constantly changing pattern.
Estrogen goes up at a certain time to make cells mature and eggs be ready for possible fertilization. After the egg matures and can thus be possibly fertilized, the estrogens work is done for a while. It should then go down.
As it goes down, progesterone should be going up because the egg may get fertilized. So the progesterone should stay up for a few days to see if the egg gets fertilized. If it does, then the progesterone amounts should stay up. If it does not get fertilized, the progesterone levels should go down.
Sort of like a waltz, with the amounts of the hormones interacting and changing amounts at different times. Too much estrogen causes too much tissue to grow, leading to increased pain and bleeding before and during the period.
The only way I am aware of to check where the hormones are throughout the entire month is by using a saliva test. You get a kit, take a saliva test every three days throughout your period, and send those saved samples (all labeled correctly and stored in the refrigerator) to the lab. What comes back is a graphic to show the all important pattern. There you can see what goes where and when. And see if you have too much estrogen in parts of the cycle where it should have actually come down. Too much estrogen compared to progesterone is what causes increased pain and bleeding because the "estrogen dominance" causes too many cells to grow for too long.
Using hormone replacement therapy - "natural" or unnatural does not and cannot help the organs heal to then produce the right amounts. Some types of treatment can help the organs heal - and is some cases totally heal - so the balance through the cycle is correct and then the endometriosis is greatly reduced or gone. Most MDs are very unaware of this and may even say it can't be done. I don't know why they don't explore more. I have always considered it part of my job as a natural health doc.