Does progesterone thicken uterus lining or stop it growing?Watch
I have found many sources which say both things, which is frustrating, I don't see how it can be both.
Also I also can't find anything on the role of uterus contractions are on menstruation.
During the period strong contractions cut off blood to the lining, which causes it do die during menstruation, but do the physical contractions themselves cause the lining to fall off, or does it just fall off on its own? And what is the point of the uterus contractions which happen throughout the throughout the entire cycle and not just during the period?
Sources on progesterone and its effect on the uterus lining:
In the epithelial cells estradiol-17ß (E2) stimulates cell division whereas progesterone (P4) inhibits this E2induced cell proliferation while at the same time preparing the epithelium for the reception of the blastocyst prior to implantation
the scientists identified a protein, called Hand2, that assists in the preparation of the uterine lining for implantation. This protein is triggered by progesterone, stopping the growth of the uterine lining at the optimal thickness for embryo implantation.
"(E2) stimulates a synchronized wave of DNA synthesis and cell division in the epithelial cells, while pretreatment with progesterone (P4) completely inhibits this E2-induced cell proliferation."
Women who have menstrual cycles longer than 35 days might not be making progesterone, which prevents the uterine lining from growing too much.
Progestins not only stop endometrial growth, but also provide support and organize the endometrium so that sloughing occurs in an organized fashion.
"progesterone completes the development of the uterus lining, which thickens" - EDEXCEL IGCSES Biology
"Progesterone causes the endometrial lining to thicken and become more vascular to support a developing embryo"
"The progesterone causes the endometrium to continue to thicken"
"Progesterone helps to thicken the endometrial lining"