PROMPT: Prospective Meta-analysis for Pessary Trials Study Protocol

Area of Science:

• Maternal-fetal medicine
• Perinatology
• Obstetrics

Background:

• Preterm birth (<37 weeks gestation) is a major cause of infant mortality and long-term disability.
• A short cervix in the second trimester is a significant predictor of spontaneous preterm birth.
• Previous studies on the effectiveness of Arabin pessary for preventing preterm birth in singleton gestations with short cervix have yielded conflicting results.

Purpose of the Study:

• To establish an international collaborative of randomized trials investigating the use of pessary for singleton and twin gestations with a short cervix.
• To conduct a prospective individual patient data (IPD) meta-analysis of these trials.

Main Methods:

• Formation of the PROspective Meta-analysis of Pessary Trials (PROMPT) collaboration in November 2014.
• Agreement on IPD meta-analysis hypotheses, eligibility criteria, and core outcome measures for singleton and twin gestations.
• Primary outcome: composite of fetal death or preterm delivery before 32 weeks' gestation; secondary outcomes include maternal and neonatal morbidities.

Main Results:

• Results are to be published in phases as individual studies conclude.
• The first phase of results from singleton and twin pessary trials is anticipated in late 2022.
• Updates will be provided as participating trials are completed and published.

Conclusions:

• A meta-analysis of pessary trials is underway to clarify its efficacy in preventing preterm birth.
• Short cervical length is a validated predictor of preterm birth.
• Further results from the PROMPT collaboration will inform clinical practice regarding cervical support.