Short answer: Crinone 8% (progesterone gel) and Endometrin (progesterone insert) are both used vaginally for progesterone support in IVF and other ART.12 Crinone 8% is usually 90 mg once a day; Endometrin is 100 mg two or three times a day, starting the day after egg retrieval. Crinone 4% is also approved for stopped periods. Neither label names a trial against the other.
| Crinone (progesterone gel) | Endometrin (progesterone insert) | |
|---|---|---|
| Approved for | 8%: progesterone support or replacement in ART; 4%: secondary amenorrhea (8% if 4% fails)1 | Support implantation and early pregnancy in ART, women under 352 |
| Form | Gel in single-use applicators, 45 mg (4%) or 90 mg (8%)1 | 100 mg vaginal insert2 |
| ART dose | 90 mg once a day; twice a day with partial or complete ovarian failure1 | 100 mg two or three times a day, from the day after egg retrieval2 |
| How long | If pregnant, up to 10 to 12 weeks1 | Up to 10 weeks in total2 |
| Common side effects | IVF study: breast enlargement 40%, constipation 27%, sleepiness 27%, nausea 22%1 | Pain after egg retrieval 28% / 25%, abdominal pain 12%, nausea 8% / 7%, OHSS 7% (808 women)2 |
| Missed dose | Use when remembered1 | Use when remembered, without going over the daily dose2 |
| Boxed warning | None1 | None2 |
The Endometrin label's main study compared 100 mg twice and three times a day with a vaginal active comparator that the label does not name. Pregnancy rates were 39% and 42%, and both were non-inferior to the comparator. In women 35 to 42, results did not meet the non-inferiority mark, and the label says efficacy at 35 and older has not been clearly established.2 The Crinone label does not report a trial against Endometrin.1
Side effects were counted in studies without a placebo group, so they include symptoms of the IVF process itself. These numbers come from separate trials with different people, lengths and methods, so they are not a head-to-head comparison.
Which product and schedule to use is your fertility team's call. More detail: Crinone side effects, Endometrin side effects, the Crinone and Endometrin dosing schedules, and the Progesterone (oral) guide.