BACKGROUND AND PURPOSE: 

• Cruz-Melguizo et al. (Obstetrics & Gynecology, 2018) compared the effectiveness of a cervical pessary and vaginal progesterone for preterm birth prevention

METHODS: 

• Multicenter, open-label, randomized, noninferiority trial (RCT)  
• Participants 
  • Singleton pregnancies  
  • Cervical length ≤25 mm  
    • transvaginal ultrasonography at 19-22 weeks  
• Subjects were randomized to receive either 
  • Cervical pessary placement  
  • Vaginal progesterone  
    • 200 mg micronized progesterone per day  
    • Vaginal route 
    • Self-administered, preferably before going to bed 
• Treatments  
  • Initiated between 20w1d and 23w6d 
  • Stopped between 37w0d and 37w4d 
• Primary outcome: Proportion of spontaneous preterm delivery <34 weeks  
• Secondary outcomes  
  • Proportion of spontaneous preterm births <37 and <28 weeks | Rate of PROM <34 and <37 weeks | Need of tocolysis and corticosteroid | Vaginal side effects | Maternal outcomes such as rate of chorioamnionitis etc.| Newborn outcomes such as birthweight and adverse events (e.g., perinatal death etc.)  
• Sample size: 254 women were required to show noninferiority of the pessary to progesterone 
  • Noninferiority margin of 4% with a 0.025 one-sided α level (i.e., if the 95% CI upper bound exceeds 4%, the pessary could not be deemed noninferior) 
  • Statistical power of 80% 
  • Assumed dropout rate of 5%

RESULTS: 

• 254 patients were enrolled and 246 included in the intention-to-treat analysis 
• The rate of spontaneous delivery before 34 weeks of gestation was 
  • 14% (n=18/127) in the pessary group 
  • 14% (n=17/119) in the progesterone group 
  • Risk difference: −0.11% (95% CI −8.85% to 8.62%; P=.99) 
  • Noninferiority was not shown for the pessary 
• Adverse events were higher in the pessary group compared to progesterone  
  • Incidence of increased vaginal discharge: 87% vs 71% (P=.002) 
  • Discomfort: 27% vs 3% (P<.001)

CONCLUSION: 

• Cervical pessary was not noninferior to vaginal progesterone 
  • 95% CI of the difference exceeded the 4% prespecified non-inferiority margin of 4%  
• Cervical pessary was associated with increased vaginal discharge and discomfort  
• Authors recommend vaginal progesterone as the first line treatment as a “first option” but 

…the pessary could be considered a similar effective alternative and could be a preferred choice for women reluctant to use daily medication

Learn More – Primary Sources: 

Cervical Pessary Compared With Vaginal Progesterone for Preventing Early Preterm Birth: A Randomized Controlled Trial

Related ObG Topics:

SMFM Statement: Choice of Progestogen for Preterm Birth Prevention

Short Cervix and Risk for Preterm Birth: Do Pessaries Work? 

Can Cervical Pessaries Prevent Preterm Birth?

PoPPS Study: Does Pessary Use In Women with a Short Cervical Length Prevent Preterm Birth?