Vaginal Progesterone Trade Names and Formulations for Short Cervix/Cervical Insufficiency
For treatment of short cervix (cervical insufficiency), use either 90-mg (8%) progesterone gel (brand name Crinone or Prochieve) or 200-mg micronized progesterone capsules (brand name Prometrium or generic equivalents) administered vaginally daily. 1
Recommended Formulations
The two most studied and recommended formulations are:
- 90-mg (8%) vaginal progesterone gel: This is typically marketed as Crinone or Prochieve 1
- 200-mg micronized progesterone capsules: Available as Prometrium (brand) or generic micronized progesterone, used off-label vaginally 1, 2
Both formulations have equivalent efficacy for preventing preterm birth in women with short cervix, and there is insufficient data to recommend one specific formulation over the other. 1
Clinical Indications and Dosing
Vaginal progesterone is strongly recommended (GRADE 1A) for asymptomatic individuals with singleton gestation and transvaginal cervical length ≤20 mm diagnosed before 24 weeks of gestation. 1
For cervical length 21-25 mm, vaginal progesterone should be considered based on shared decision-making (GRADE 1B). 1
Treatment Protocol:
- Start: Upon diagnosis of short cervix (before 24 weeks gestation) 1
- Continue: Daily administration until 36 weeks of gestation 2
- Route: Vaginal administration for both formulations 1, 2
Important Clinical Considerations
Off-Label Use Requires Counseling
The use of vaginal progesterone for short cervix indication is currently off-label in the United States and requires patient counseling. 1, 2 The FDA did not approve vaginal progesterone for this indication despite strong evidence of benefit, partly because the PREGNANT Trial failed to demonstrate benefit when only US patients were analyzed, and concerns about efficacy in Black patients and those with obesity. 1
Contraindications - Critical Safety Issue
Micronized progesterone capsules (Prometrium) contain peanut oil in the excipients and are absolutely contraindicated in individuals with severe peanut allergies, including anaphylaxis. 1
For patients with peanut allergies, use vaginal gel formulations (Crinone/Prochieve), which do not contain peanut oil. 1
What NOT to Use
Do NOT prescribe 17-alpha-hydroxyprogesterone caproate (17-OHPC/Makena) for treatment of short cervix (GRADE 1B). 1 The FDA withdrew approval of 17-OHPC on April 5,2023, due to lack of efficacy, and it has not consistently shown reduction in spontaneous preterm birth even in the setting of short cervical length. 1
Evidence of Benefit
Vaginal progesterone reduces preterm birth at <32 weeks by 36% (RR 0.64,95% CI 0.48-0.86) and reduces composite neonatal morbidity and mortality by 41% (RR 0.59,95% CI 0.38-0.91). 1 Additional benefits include reductions in respiratory distress syndrome, NICU admission rates, intraventricular hemorrhage, neonatal mortality, and low birthweight. 3