Abnormal Uterine Bleeding and Medroxyprogesterone
If you have abnormal vaginal bleeding due to a hormonal imbalance, your healthcare provider may recommend medroxyprogesterone (Provera®). Although this drug is available in both tablet and injection form, only the tablet form is approved for this use.
To understand how medroxyprogesterone works for this purpose, it's helpful to know that it is a synthetic form of progesterone, a progestin hormone. It works by replacing progesterone when the body is not making enough of it.
When medroxyprogesterone is given for several days and then stopped, vaginal bleeding occurs. This bleeding is called "withdrawal bleeding" because it happens in response to the withdrawal of progestin. Withdrawal bleeding usually occurs three to seven days after the hormone is stopped. The drop in progestin levels causes the uterine lining (the endometrium) to slough off and bleed. This can help restore regular periods in women who have been having irregular periods.
(To learn more about how this drug works to treat abnormal uterine bleeding, click What Is Medroxyprogesterone Used For?. This article also lists the drug's other uses and explains whether it is approved for use in children and older adults.)