progesterone
noun
pro·ges·ter·one
prō-ˈje-stə-ˌrōn 
: a female steroid sex hormone C21H30O2 that is secreted by the corpus luteum to prepare the endometrium for implantation and later by the placenta during pregnancy to prevent rejection of the developing embryo or fetus
Examples of progesterone in a Sentence
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Women who begin menstruating early — especially before age 12 — and therefore have more menstrual cycles over their lifetime have a slightly higher risk for breast cancer, likely because they’re exposed to the hormones estrogen and progesterone for longer, according to the American Cancer Society.
—
Miriam Fauzia, Dallas Morning News, 10 Feb. 2026
The other half who had a positive test were told and their doctors started them on a regimen of low-dose aspirin, a vaginal suppository of progesterone and weekly check-in calls with a nurse.
—Nicole Villalpando, Austin American Statesman, 7 Feb. 2026
Prescribed to women with a uterus, progesterone is released into the bloodstream and travels to the organs and tissues where it’s needed.
—Bonnie Vengrow, Flow Space, 6 Feb. 2026
Mifepristone works by blocking progesterone, a hormone that the body needs to continue a pregnancy.
—Arthur Jones Ii, ABC News, 14 Jan. 2026
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Miriam Fauzia, Dallas Morning News, 10 Feb. 2026
The other half who had a positive test were told and their doctors started them on a regimen of low-dose aspirin, a vaginal suppository of progesterone and weekly check-in calls with a nurse.
—Nicole Villalpando, Austin American Statesman, 7 Feb. 2026
Prescribed to women with a uterus, progesterone is released into the bloodstream and travels to the organs and tissues where it’s needed.
—Bonnie Vengrow, Flow Space, 6 Feb. 2026
Mifepristone works by blocking progesterone, a hormone that the body needs to continue a pregnancy.
—Arthur Jones Ii, ABC News, 14 Jan. 2026
See All Example Sentences for progesterone
Cite this Entry
“Progesterone.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/progesterone. Accessed 14 Feb. 2026.
Copy CitationKids Definition
progesterone
noun
pro·ges·ter·one
prō-ˈjes-tə-ˌrōn
: a hormone that is produced by the corpus luteum and causes the uterus to change so that it provides a suitable environment for a fertilized egg
Medical Definition
progesterone
noun
pro·ges·ter·one
prō-ˈjes-tə-ˌrōn
: a female steroid sex hormone C21H30O2 that is secreted by the corpus luteum to prepare the endometrium for implantation and later by the placenta during pregnancy to prevent rejection of the developing embryo or fetus
Note: Synthetic steroids (such as progestins) that function similarly in the body are sometimes also referred to as progesterones.
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