The cause of endometriosis is unclear, and with an unclear reason for a pathology to be present, a targeted treatment becomes difficult – each women is going to respond to different therapies with variable outcomes. What is known about endometriosis though, is that there is significant disregulation with respect to the estrogen and progesterone receptors at the level of the endometrium.
Estrogen stimulates the proliferative component of the endometrial lining, stimulating it to grow more robust during the follicular phase of the cycle, and then progesterone comes in after ovulations to counter act the proliferation, and promote the secretory phase of the endometrial lining development, stopping growth but preparing the lining for potential implantation.
What can be seen in endometriosis, is a progesterone resistant endometrial lining. What does that mean? The progesterone receptors are not as responsive to the progesterone signals as they should be. This results in over stimulation of estrogen, because progesterone isn’t being received at the endometrium to counter balance it, causing the endometrial tissue to build and build – potentially in the wrong spaces too. This excess endometrial lining can result in increased cramping during menses to try and shed the extra tissue that has been built up, and if there is excess endometrial lining in an area it’s not supposed to be (ie outside of the uterus) that can be inflammatory to that environment.
So as well as progesterone resistance contributing to pain, this also plays a major role with respect to fertility. The uterine lining needs adequate progesterone exposure to go from proliferatory –> secretory after ovulation the menstrual cycle in order for a blastocyst to be able to implant properly. Queue up progesterone suppositories as a potential fertility treatment option in endometriosis!
If you’ve been following along on my videos, where I’ve discussed the menstrual cycle, estrogen and progesterone, you’ll see that the whole cycle and the function of these hormones work in a fine dance with respect to each other, and endometriosis is an example of when that balance is off and a pathology can arise.