Dydrogesterone
An orally active retroprogesterone structurally close to progesterone but more selective. Used for endometrial protection in HRT, luteal support, threatened/recurrent miscarriage and dysfunctional bleeding, with minimal androgenic or estrogenic activity.
01 Overview
Dydrogesterone is a retrosteroid: a progesterone isomer with a modified stereochemistry that confers high oral bioavailability and selective progesterone-receptor activity without meaningful androgenic, estrogenic or glucocorticoid effects. This selectivity gives a favourable side-effect profile.
It is used to oppose estrogen in HRT, to support the luteal phase in fertility treatment, and in some regions for threatened and recurrent miscarriage, where trial evidence is mixed but generally supportive. It does not suppress ovulation at therapeutic doses.
02 Mechanism
Selective progesterone-receptor agonist (retroprogesterone) that induces secretory endometrial transformation without significant androgenic, estrogenic or mineralocorticoid activity.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Endometrial protection / luteal support | 10–30 mg/day | Oral | 10-20 mg/day cyclic; up to 30-40 mg for threatened miscarriage. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Endometrial protectionOpposes estrogen on the endometrium with good tolerability. | Clinical | ||
| Luteal / early pregnancy supportSupports luteal phase; used for threatened miscarriage in some guidelines. | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Headache / migraineHeadache is among the more frequent complaints. | Mild | Common | Clinical | |
| Breakthrough bleedingOccasional irregular bleeding. | Mild | Uncommon | Clinical |