Short answer: The Endometrin label dose is one 100 mg vaginal insert two or three times daily, starting the day after egg (oocyte) retrieval and continuing for up to 10 weeks total. Efficacy in women 35 and older has not been clearly established, and the right dose for them is not set. A forgotten dose is used when remembered, without going over the daily dose.
This is what the FDA label says. Follow your prescriber. Your prescriber may use a different dose or pace than the label's standard schedule.
What Endometrin is approved for: Endometrin is a progesterone vaginal insert approved, as part of an Assisted Reproductive Technology (ART) program, to support embryo implantation in infertile women under 35 by supplementing corpus luteum function, and to maintain pregnancy after implantation up to 10 weeks (section 1). Efficacy in women 35 and older has not been clearly established (section 2).
Source
ENDOMETRIN (progesterone) vaginal insert, prescribing information and Patient Information. Ferring Pharmaceuticals. DailyMed, version published August 5, 2026. DailyMed setid 2ba50fa9-b349-40cb-9a4b-1af8faa4ec09
One 100 mg insert is placed in the vagina with a disposable applicator, two or three times a day, starting the day after oocyte retrieval and continuing up to 10 weeks total (section 2).
The Patient Information says to unwrap the applicator, set one insert snugly in the end, place it well into the vagina while standing, sitting or lying with knees bent, push the plunger and throw the applicator away.
Other vaginal products are not used during Endometrin treatment (section 7, Patient Information).
The table below is the label's schedule, from the Dosage and Administration section. Numbers are copied exactly; the section is in brackets.
| Item | What the label says |
|---|---|
| Dose | 100 mg administered vaginally two or three times daily |
| Start | The day after oocyte retrieval |
| Duration | Up to 10 weeks total |
| Women 35 and older | Efficacy not clearly established; appropriate dose not determined |
| Pack | 21 vaginal inserts with 21 disposable applicators |
In the main study, both 100 mg twice daily and three times daily were non-inferior to the active comparator for pregnancy rates (39% and 42%), and women who became pregnant used Endometrin for a total of 10 weeks.
In women 35 to 42 and those with FSH of 10 to 15 IU/L, pregnancy rates did not meet the non-inferiority criteria.
Endometrin is stopped if a heart attack, stroke, blood clot, thrombophlebitis or retinal thrombosis is suspected.
Women with a BMI over 34 kg/m2 were not studied, so efficacy in them is unknown.
If a dose of Endometrin is forgotten, it is taken as soon as remembered, but no more than the daily dose is used. The Patient Information says to call the doctor if too much is used.
More on this: missed a dose of Endometrin.
In Dose Track you set up Endometrin as a protocol with the dose and schedule your prescriber gave you. A protocol can hold dose steps, each with its own dose and length in days or weeks, so a step-up plan like the one on the label can be entered once and the app moves to the next step on its own. Reminders follow the schedule, and every dose is logged with the date and time, so you can see which step you are on and when your last dose was. The app follows what you enter; it does not choose or change a dose.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.