# Estrogen --- **Estrogen** (sometimes spelled **oestrogen**) is a [[hormone|sex hormone]] that is secreted by the [[ovaries]]. It is produced in large amounts of puberty for AFAB people, during which time it helps develop the ovaries, uterus, vagina and breasts. [[Follicle-stimulating hormone]] from the pituitary gland stimulates the release of estrogen from the ovaries. ```smiles CC12CCC3C(C1CCC2O)CCC4=C3C=CC(=C4)O ``` ## Estrogen During the Menstrual Cycle After puberty it is released at various levels during the [[menstrual cycle]]. There is a certain basal level of estrogen during the follicular phase, which ramps up just before ovulation, and then another gentler spike during the back half of the luteal phase. ![[menstrual cycle.png]]**** During the menstrual cycle estrogen does things such as: - build up [[uterus|endometrium]] for implantation - trigger ductal development for lactation - increase vaginal discharge (I don't know why) ## Estrogen During Pregnancy If fertilization occurs estrogen continues to be produced by the [[corpus luteum]]. Around week 10, the [[placenta]] takes over production and the corpus luteum regresses. ![[pregnancy hormones.png]] During pregnancy, estrogen: - is a major factor in [[labor]] preparation - grows and prepares the myometrium - has a role in prostaglandin synthesis for [[labor]] preparation ## Meds - Estrogen replacement - Estrogen is sometimes given to [[menopause|post-menopausal]] women as a form of [[hormone replacement therapy|HRT]]. - Estrogen is sometimes given to trans-women as a form of [[hormone replacement therapy|HRT]]. - Estrogen blockers - **Tamoxifen** (brand name: Nolvadex, Soltamox) is an estrogen blocker that can be used to treat [[breast cancer]] ___