Estradiol for tissue of the reproductive organs, supporting the lining of the vagina, the cervical glands, the endometrium, and the lining of the fallopian tubes. It enhances growth of the myometrium. Estradiol appears necessary to maintain oocytes in the ovary. During the menstrual cycle, estradiol produced by the growing follicles triggers, via a positive feedback system, the hypothalamic-pituitary events that lead to the luteinizing hormone surge, inducing ovulation. In the luteal phase, estradiol, in conjunction with progesterone, prepares the endometrium for implantation. During pregnancy, estradiol increases due to placental production. The effect of estradiol, together with estrone and estriol, in pregnancy
Topical progesterone of tissue exposure to progesterone with this route of administration. These findings provide a possible explanation for how some studies found antiproliferative and atrophic changes in the endometrium with topical progesterone. However, elevated levels of progesterone in the endometrium with topical progesterone have not yet been demonstrated. Concern has been raised regarding topical progesterone in that the effects of such supraphysiological levels of progesterone in tissues are unknown and hence the potential for harmful effects has not been ruled out. Salivary monitoring of progesterone levels in women using topical progesterone and adjustment of dosage as necessary has been suggested as