Medroxyprogesterone
Medroxyprogesterone acetate (MPA, Provera) is a synthetic progestin used in combination hormone therapy to protect the uterine lining.
How it works
Medroxyprogesterone acetate (MPA) is a synthetic progestin — it binds progesterone receptors and prevents endometrial hyperplasia when used with estrogen, but it is chemically distinct from bioidentical progesterone and has a different receptor binding profile. MPA was the progestin used in the Women's Health Initiative (WHI) trial, the large study that raised concerns about combined hormone therapy risk (particularly breast cancer and cardiovascular events with Prempro, which combined conjugated equine estrogens with MPA). Most subsequent reanalysis has suggested the risk signals from WHI were most specific to the MPA-containing arm and to older postmenopausal women initiating therapy late.
Unlike bioidentical progesterone, MPA does not produce the GABA-A neurosteroid metabolites that provide sleep benefit — and some research suggests MPA may partially attenuate the cardiovascular benefits of estradiol. For people who tolerate MPA and for whom it is appropriate, it is an effective progestogen with decades of clinical data. For people prioritizing the sleep benefit of progesterone or who are switching from synthetic progestins, the comparison between MPA and bioidentical progesterone is worth discussing with a physician.
How to track Medroxyprogesterone
- Breakthrough bleeding or spotting — on sequential or continuous regimens, bleeding patterns are diagnostically important and should be logged with dates and description.
- Mood changes — some people report mood effects with MPA that differ from bioidentical progesterone; tracking mood alongside the start or dose change of MPA is useful.
- Sleep quality — unlike bioidentical progesterone, MPA does not produce a sedating neurosteroid effect; if sleep is a concern, tracking it alongside progestin type helps make the comparison.
- Breast tenderness — a common side effect; track alongside your estrogen dose to help distinguish the two contributors.
- Side effects: bloating, headache, irritability.
- Log all bleeding and spotting episodes with dates and description — breakthrough bleeding is the most clinically important tracking variable on any progestogen regimen.
- If you switched from bioidentical progesterone to MPA (or vice versa), use the switch date as a baseline and track sleep and mood separately for six to eight weeks.
- Track breast tenderness with timing relative to your estrogen and progestin schedule — the pattern can help identify which component is contributing.
- Note mood changes with timestamps and the phase of your regimen — if you are on a cyclic regimen, mood changes that cluster around progestin days are a recognized pattern worth flagging.
- Log any MPA dose changes with the exact date so before-and-after comparisons are clean.
Questions to ask your physician
- I've been logging breakthrough bleeding on [dates and description] — what does that pattern suggest about my regimen?
- My mood tracking shows [pattern] that appears to correlate with MPA days on my cyclic regimen. Is that a recognized progestin effect, and does it suggest switching to a different progestogen?
- My sleep log has not improved with my HRT regimen. Given that MPA doesn't have the neurosteroid sleep effect of bioidentical progesterone, would switching progestogens be worth discussing?
- My breast tenderness log shows [pattern] — does the timing suggest the estrogen or progestin component is the more likely contributor?