A Randomized Trial of a Cervical Pessary to Prevent Preterm Singleton Birth

Jordan Alava, Mercer University College of Pharmacy

A meta-analysis assessing the effectiveness of a cervical pessary to prevent preterm birth (PTB) concluded that it is a safe, affordable, and reliable alternative for preventing PTB in a population of at-risk pregnant women who have been screened for cervical length assessment at the midtrimester scan.  [1]

According to the Centers for Disease Control and Prevention (CDC), preterm birth is the greatest contributor to infant death as well as the leading cause of long-term neurological disabilities in children.  The CDC reported that 10% of infants born in the United States in 2014 were preterm births.  [2]

Title: A Randomized Trial of a Cervical Pessary to Prevent Preterm Singleton Birth
Design Multicenter, randomized, controlled; N= 932
Objective To determine the effectiveness of a cervical pessary in PTB
Study Groups Pessary (n= 465); control (n= 467)
Methods Girls and women pregnant with singletons were randomly assigned to either the cervical pessary group or the control group.  Those in the pessary group had one inserted through the vagina and placed upward around the cervix while in the recumbent position.
Duration September 2008 – January 2013
Primary Outcome Measure Spontaneous delivery before 34 weeks of gestation
Baseline Characteristics There were no significant differences between the pessary group and the control group.  The median age was 30.1 years in the pessary group and 29.5 in the control group.  In both groups, approximately 65% were white with a median gestation week of 23.5 and median cervical length of 20mm.
Results   Pessary group (n= 465) Control group (n= 467) Odds Ratio (95% CI) p value
No. of participants included in analysis 460 464    
Spontaneous delivery at <34 weeks, No. (%) 55 (12.0) 50 (10.8) 1.12 (0.75-1.69) 0.57
Abbreviations: confidence interval (CI)
Adverse Events Common Adverse Events: Intravascular hemorrhage (2.0%), respiratory distress syndrome (6.2%), retinopathy of prematurity (1.1%), necrotizing enterocolitis (1.3%)
Serious Adverse Events: Fetal death (1.7%), neonatal death (1.5%)
Percentage that Discontinued due to Adverse Events: N/A
Study Author Conclusions Among girls and women with singleton pregnancies who had a short cervix, a cervical pessary did not result in a lower rate of spontaneous early preterm delivery than the rate with expectant management.

The results of this study did not demonstrate a clinically significant difference in the prevention of preterm singleton births when compared to standard treatment modalities.  The rate of spontaneous preterm delivery was similar between groups with a higher incidence of perinatal death in the pessary group.  One major limitation to this study was that neither the participants nor researchers were blinded which could have affected the medical decision making process and introduced bias.


  1. Liem SM, Van pampus MG, Mol BW, Bekedam DJ. Cervical pessaries for the prevention of preterm birth: a systematic review. Obstet Gynecol Int. 2013;2013:576723.
  2. Preterm Birth. Centers for Disease Control and Prevention. 2015. Available at: http://www.cdc.gov/nchs/data/databriefs/db124.htm. Accessed: March 17, 2014.
  3. Nicolaides KH, Syngelaki A, Poon LC, et al. A Randomized Trial of a Cervical Pessary to Prevent Preterm Singleton Birth. N Engl J Med. 2016;374(11):1044-52.

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