Question for Progestin Test

[GomerPyle]

Hi all,

I understand that if there's bleeding after progestin withdrawl, then that indicates anovulation (low progesterone) as the cause of amenorrhea.

My question is, why does low progesterone cause amenorrhea? In my mind, it'd cause heavy menstration since you can't maintain the endometrial lining formed by estrogen.

Thanks for your time!

---

Members don't see this ad.

 

[DerpStore]

Low progesterone doesn't cause amenorrhea. Failure to ovulate however will result in low progesterone. If the follicle does not rupture, it does not become the corpus luteum which is the progesterone factory in our body.

The progestin withdrawal test is used to assess estrogen levels. If estrogen is normal, then withdrawal of progestin will cause bleeding. If estrogen is low, withdrawal will have no effect as the endometrium will be atrophic.

And you are correct- the lack of progesterone does lead to bleeding, but this is not the regular cyclical bleeding. An anovulatory cycle (where corpus luteum does not make progesterone) will result in asynchronous shedding of portions of the endometrium unaccompanied by the normal vasoconstriction.

 

[GomerPyle]

Low progesterone doesn't cause amenorrhea. Failure to ovulate however will result in low progesterone. If the follicle does not rupture, it does not become the corpus luteum which is the progesterone factory in our body.

The progestin withdrawal test is used to assess estrogen levels. If estrogen is normal, then withdrawal of progestin will cause bleeding. If estrogen is low, withdrawal will have no effect as the endometrium will be atrophic.

And you are correct- the lack of progesterone does lead to bleeding, but this is not the regular cyclical bleeding. An anovulatory cycle (where corpus luteum does not make progesterone) will result in asynchronous shedding of portions of the endometrium unaccompanied by the normal vasoconstriction.

Thanks for your response. If you don't mind, how does anovulation come into play with the progestin test? Wiki says that if progestin withrdawl induces bleeding, then the cause of amenorrhea is anovulation. I'm still having a hard time putting that together.

 

[DerpStore]

We can make an equation. Menstruation = estrogen exposure + responsive endometrium + progesterone + progesterone withdrawal. The complaint is that there is a problem with menstruation, and it can be a problem with any of the terms on the right. So in the progesterone test we are saying, lets addback progesterone and the progesterone withdrawal. If this causes menstruation, then we know that the estrogen exposure + responsive endometrium term is intact. And therefore we can say that the problem is with the progesterone + progesterone withdrawal component of the equation. Then we remember that normally after the LH surge, the dominant follicle ruptures and releases an oocyte, becoming the corpus luteum, which secretes progesterone. So naturally if the dominant follicle fails to become the corpus luteum, which is called anovulation, then we don’t get progesterone production- which is the problem we diagnosed with our positive progestin challenge. A common cause of this is polycystic ovarian syndrome.


A negative progestin test will however indicate that there is a problem with the remaining terms, estrogen+responsive endometrium. So now you would add estrogen and progesterone. If this fails to cause bleeding, then you know the problem is with the responsiveness of the endometrium. One cause would be Asherman’s syndrome. If estrogen addback does cause bleeding, then somethings up with the HPA axis (hyper/hypogonadotropic hypogonadism)