Medroxyprogesterone: what it treats, how to take it, side effects
Last updated September 3, 2026.
Medroxyprogesterone is a progestin - a lab version of progesterone that stops the growth of the uterine lining and steadies the cycle. You may know it as Provera. It regulates bleeding, restarts absent periods, and protects the uterus when estrogen is in the picture.
What does it treat?
Abnormal periods and irregular vaginal bleeding; bringing on a normal cycle in women who menstruated normally in the past but have gone at least 6 months without a period and are not pregnant or in menopause; and preventing overgrowth of the uterine lining - which may lower uterine-cancer risk - in people taking estrogen.
How do you take it?
A tablet once a day, but only on certain days of a regular monthly cycle - the calendar is the prescription, so same time of day on your scheduled days. It controls the condition; it does not cure it, so keep the monthly rhythm even when things feel normal. Missed dose: take it when you remember unless the next one is close; never double up.
Side effects to know
- Common: tender breasts or breast discharge, changes in menstrual flow, irregular spotting, acne, facial hair growth or scalp hair loss, insomnia, drowsiness, upset stomach, and weight gain or loss.
- Serious - call your doctor immediately: pain, swelling, warmth, redness, or tenderness in one leg only; slow or difficult speech; dizziness or faintness; weakness or numbness of an arm or leg; shortness of breath; coughing up blood; sudden sharp or crushing chest pain; a fast or pounding heartbeat; sudden vision changes, double or blurred vision, or bulging eyes; missed periods; depression; yellowing of the skin or eyes; fever; hives, rash, or itching; trouble breathing or swallowing; and swelling of the hands, feet, ankles, or legs.
Who should not take it?
Flag a history of breast or female-organ cancer, unexplained vaginal bleeding, a missed abortion, blood clots in the legs, lungs, brain, or eyes, stroke or mini-stroke, seizures, migraines, depression, asthma, diabetes, and heart, kidney, or liver disease. It should never be used to test for pregnancy or to prevent miscarriage - it has not been shown to prevent miscarriage and can harm a fetus, so if you become pregnant, call your doctor immediately. Two risk facts to hold plainly: laboratory animals given medroxyprogesterone developed breast tumors - whether it raises breast-cancer risk in humans is unknown - and it may increase the chance of a blood clot traveling to the lungs or brain. Both are explicit conversations with your doctor.
When is it an emergency?
One-leg swelling, coughing blood, crushing chest pain, speech trouble, or sudden vision loss is a 911 call - the clot and stroke cluster. For an overdose, call Poison Control at 1-800-222-1222. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
What a Pymander AI doctor consult looks like
Illustrative example, not a real member's messages.
Common questions
Why do I take Provera only on certain days of the month?
Because the goal is to mimic what progesterone does in a natural cycle: rise for a stretch, then fall. MedlinePlus describes it as once daily on certain days of a regular monthly cycle - when you stop the tablets each cycle, the hormone drop triggers the uterine lining to shed, which is the bleed that resets things. The calendar is not bureaucracy; it is the mechanism.
Why did I get a period after finishing the tablets?
That is the prescription working. The days on the drug build the signal, the stop creates the drop, and the drop produces a withdrawal bleed - typically within days of the last tablet. For absent periods, that bleed is the proof the cycle machinery still runs. If the bleed never comes after the course, that is a call to your doctor, because the reason for the silence needs a look.
Why did my doctor ask about blood clots and migraines?
Medroxyprogesterone may increase the chance of a blood clot traveling to the lungs or brain, per MedlinePlus - so clot history in the legs, lungs, brain, or eyes, plus stroke or mini-stroke history, are decision-shaping facts. The serious-effects list reads as a clot-and-stroke recognition chart: one-leg swelling, coughing blood, crushing chest pain, speech trouble, sudden vision changes. Rare, and never to be waited out.
Can I use Provera to prevent a miscarriage?
No - MedlinePlus is explicit: medroxyprogesterone should never be used to test for pregnancy or to prevent miscarriage in early pregnancy. It has not been shown to prevent miscarriage and may harm the fetus. If you could be pregnant or become pregnant while taking it, call your doctor immediately.
Why did my doctor pair this with my estrogen?
Estrogen alone grows the uterine lining continuously, and unopposed growth is the endometrial-cancer pathway. Medroxyprogesterone stops that growth - MedlinePlus says it is used to prevent overgrowth of the uterine lining and may decrease the risk of uterine cancer in people taking estrogen. If you have a uterus and take estrogen, the progestin is the protection half of the pair.
What happens if I miss a dose of medroxyprogesterone?
Take it as soon as you remember, unless it is almost time for the next one - then skip it and never double up. Because the tablets run on a cycle calendar, a missed day near the end of a course can shift the bleed timing; if you miss more than one, call your prescriber for the adjustment rather than guessing.