# Progesterone
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**Progesterone** is a [[hormone]] that is produced by the [[ovaries]] and stimulated by [[follicle-stimulating hormone|FSH]]. Broadly speaking progesterone helps the body prepare for pregnancy (pro-gestation). It does things like:
- build up the endometrium to form a [[uterus|decidual layer]]
- if pregnancy occurs, further production of progesterone continues to build the decidua for placental attachment
- encourages a quiescent uterus, meaning one that *doesn't* contract.
- chills out the uterus by relaxing the [[smooth muscle]] in the uterine wall
- unfortunately this can also relax other smooth muscles in the body
- in the intestines, which is why pregnant people get constipated
- in the esophageal sphincters, which is one reason why pregnant people get [[GERD]]
- develops lactiferous cells in the breast to deliver colostrum and mature milk
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## Progesterone During The Menstrual Cycle
Progesterone is released at a basal level during the follicular phase, and then surges during the luteal phase. If there is no successful fertilization levels drop down off again.
![[menstrual cycle.png]]
## Progesterone During Pregnancy
If fertilization occurs progesterone continues to be produced by the [[corpus luteum]]. Around week 10, the [[placenta]] takes over production and the corpus luteum regresses.
![[pregnancy hormones.png]]
After the [[childbirth|baby is born]]
## Meds
- antineoplastic/appetite stimulant
- **megestrol** (brand name: **Megace**) is a progestin that can is used to treat [[uterine cancer]] or help patients with [[AIDS]] boost their appetite
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