| Consensus body | Region | Recommendations for CL screening | Definition of short cervix | Guidelines for vaginal progesterone | Guidelines for timing and dosing |
| American College of Obstetricians and Gynecologists (ACOG)[1,2] | US | - With a history of sPTB: Serial endovaginal ultrasound measurement of CL beginning at 16-0/7 weeks of gestation and repeated until 24 0/7 weeks (Level A)
- No history of sPTB: Cervix should be visualized at the 18 0/7-22 6/7 weeks of gestation anatomy assessment, with either a transabdominal or endovaginal approach; serial measurements are not indicated (Level B)
| - CL ≤25 mm regardless of history
| - No prior PTB: Recommend for CL ≤25 mm in the midtrimester (Level A)
- Prior PTB: Consider vaginal progesterone versus cerclage for CL ≤25
| - Most studies used 200 mg progesterone daily; however, there are insufficient data to indicate which formulation and dose are most effective
- Start at diagnosis of short CL and continue until 36 to 37 weeks
|
| Society for Maternal Fetal Medicine (SMFM)[3] | US | - All pregnant patients between 18 to 22 weeks using a transvaginal approach (GRADE 1C)
| - CL ≤25 mm regardless of history
| - Recommend for CL ≤20 mm prior to 24 weeks (GRADE 1A)
- Consider for CL 21 to 25 mm based on shared decision-making (GRADE 1B)
| - No specific recommendation
|
| The National Institute for Health and Care Excellence (NICE)[4] | UK | - All pregnant patients should be screened by TVUS between 16+0 and 24+0 weeks
| - CL ≤25 mm regardless of history
| - Recommend for CL ≤25 mm regardless of history
| - In April 2024, the only licensed preparation of progesterone for this indication was vaginal 200 mg capsules
- Start between 16+0 and 24+0 weeks and continue until at least 34 weeks
|
| International Federation of Gynecology and Obstetrics (FIGO)[5-7] | Global | - No specific recommendations
| | - Patients at high risk of PTB (including sonographic short cervix) should be offered vaginal progesterone
| - Daily
- No specific recommendation regarding dosing
|
| Society of Obstetricians and Gynaecologists of Canada (SOGC)[8] | Canada | - All pregnant patients in the midtrimester by TVUS
| - CL ≤25 mm irrespective of risk factors
| - Recommend for CL ≤25 mm between 16 and 24 weeks (GRADE strong/moderate)
| - Micronized progesterone 200 mg daily (GRADE strong/moderate)
|
| International Society of Ultrasound in Obstetrics and Gynecology (ISUOG)[9] | Global | - Universal TVUS CL measurement at the second-trimester scan (GRADE C)
- CL measurement for prediction of PTB should be performed by TVUS (GRADE B)
- The shortest technically correct measurement of at least three CL measurements should be used
- TVS CL measurements should be performed in a standardized way, preferably by operators who have been certified by a scientific body, such as The Fetal Medicine Foundation or the Perinatal Quality Foundation (CLEAR)
| - CL ≤25 mm irrespective of risk factors
| - Recommend for CL ≤25 mm before 24 weeks
| - Micronized progesterone 200 mg every night
- Start at time of detection of the short cervix and continue until 36 weeks (GRADE A)
|
