10+ Year Member
Aug 8, 2007
Could someone please tell me if I am correct or incorrect? And if I am incorrect can can someone please correct me?

My understanding:
- Thickening of the endometrial lining in the luteal phase - if no fertilization event occurs this thick thing of tissues is kind of like ripped off - which then i guess kind of rips off some blood vessels which causes menstruation.

Also, what is the logic behind the slight increase of progesterone and estrogen in the secretory phase?
Last edited:


Moderator Emeritus
10+ Year Member
7+ Year Member
May 11, 2008
The reason for the thickening of the endometrium is to provide appropriate conditions for implantation of a fertilized egg. If an egg is not fertilized, the corpus luteum that forms after ovulation involutes and becomes the corpus albicans; this causes it to lose its secretory function. Because of this reduction of estrogens and progesterone, mainly progesterone, menstruation occurs. The endometrium, along with the blood vessels, break down (the loss of hormonal stimulation causes necrosis in the endometrium, especially the blood vessels). Uterine contractions then expel the blood and tissue.

During the secretory phase, the reason for the increased estrogen and progesterone is because estrogen promotes proliferation of the endometrium and progesterone causes the secretory function to develop (and some increase in endometrial thickness too).

Hope this helps.
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