Society for Maternal-Fetal Medicine Statement: The role of cervical pessary placement to prevent preterm birth in clinical practice

Publications Committee — 2017

There has been renewed interest in the use of the cervical pessary as an intervention to prevent preterm birth (PTB) in women at high-risk for preterm birth. Multiple randomized clinical trials (RCTs) have been published in the last several years, with conflicting results. The purpose of this statement is to summarize the findings of recent RCTs studying the use of the cervical pessary to prevent PTB and to provide guidance regarding the role of cervical pessary use in clinical practice.

Placement of a cervical pessary to treat cervical shortening was initially proposed in the late 1950s and early 1960s.1-3 Most recently, the Arabin pessary has been studied as a possible alternative to cerclage and/or vaginal progesterone therapy. The mechanism of action for pessary in the prevention of PTB is postulated to be an alteration of the uterocervical angle such that the force from the weight of the uterine contents is directed away from the internal os.4,5

The low cost and relative ease of insertion and removal as well as avoidance of medication exposure or operative procedure have been factors driving further investigation of the effectiveness of the cervical pessary.6,7 Because the Arabin pessary is constructed in such a way that the caudal portion of the device encircles the cervix, some have postulated that it may provide additional benefit by also preventing cervical dilation, deterioration of the mucous plug, and exposure of the membranes.8

The Arabin pessary appears to be associated with low rates of major complications. Most reported side effects are minor and include discomfort with placement and removal.7 In several studies, the most common side effect is an increase in vaginal discharge. Approximately 15–20% of women treated with an Arabin pessary had an amount of discharge requiring medical evaluation to exclude infection or membrane rupture.

In RCTs the rates of actual vaginal infection are similar in women with and without cervical pessary.9,10 It is unknown whether pessary exposure alters the vaginal microbiome and has an impact on the long-term maternal and/or neonatal or child outcomes. Serious adverse events (eg, cervical ischemia) are rare. Reported side effects from other pessaries, including other ring devices and the Smith-Hodge lever design, are limited but appear similar to those trials involving the Arabin pessary.11