Menstrual cycle progesterone

Progesterone therapy either during the luteal phase of the menstrual cycle or for 21 days starting on day 5 after the onset of menses results in a 32% to 50% reduction in menstrual blood loss.29 Its use has not been shown to be superior to other medical treatments, including NSAIDs.29 In addition, it is not associated with any contraceptive benefit.33... 

Progesterone is synthesized in the corpus luteum in a cycle timed to the menstrual cycle. Synthesis continues should pregnancy develop. Progestins such as megestrol acetate and medroxyprogesterone acetate find use in therapy for metastatic breast cancer. 

Figure 19.12 Representation of changes in hormone levels during the menstrual cycle. Note that LH peaks about one day before ovulation. Oestrogen has two peaks one in the Luteal phase prior to LH surge and a smaller one in the follicular phase. Progesterone peaks in the follicular phase to stimulate development of endometrium.

Oestradiol and progesterone regulate the structural and functional changes in oviducts, uterus, cervix and vagina that occur during the menstrual cycle. They provide conditions in the oviduct for the upward motility of sperm, and the downward movement of ova, and also conditions favourable for fertilisation in the oviduct and implantation in the uterus. Another effect is to stimulate vaginal secretions. 

Menstrual cycling is dependent upon the hormones secreted by the Graafian follicles. Once the primordial follicles are depleted, the secretion of oestrogen and progesterone progressively fails and menstrual cycle activity gradually decreases, a period which is characterised by irregular cycles. The differences in steroid hormone production or plasma levels between pre- and post-meno-pausal women are as follows ... 

Estradiol is the most important of the estrogens. Like progesterone, it is synthesized by the ovaries and, during pregnancy, by the placenta as well. Estradiol controls the menstrual cycle, it promotes proliferation of the uterine mucosa, and is also responsible for the development of the female secondary sexual characteristics (breast, fat distribution, etc.). 

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