This open label, multi-center, randomized controlled trial aims to compare the effectiveness of cervical pessary to vaginal progesterone for prevention of PTB in women with singleton pregnancies and a cervix ≤25 mm.~All women at 16 0/7 to 22 0/7 weeks with singleton pregnancies will undergo cervical length (CL) measurement and digital examination at screening routinely. Women with a CL ≤25 mm will be eligible for the study.~Subjects meeting the study criteria will be randomized into two groups: (1) treated with cervical pessary (Arabin) or (2) treated with 200 mg vaginal progesterone, once daily.~After written informed consent, women will be randomly assigned in a 1:1 ratio to receive a cervical pessary or progesterone. Assignment to treatment allocation will be done via a web portal hosted by HOPE Research Center, Vietnam. The randomization schedule will be computer-generated at HOPE Research Center, with a permuted random block size of 2, 4 or 6. Blinding will not be possible due to the nature of interventions.~For those who randomised to pessary group, a pessary certified by European Conformity (Arabin®, Dr Arabin GmbH & Co KG, Germany) will be inserted through the vagina, upward around the cervix by 2-4 senior clinicians, who had experienced with pessary used at each site, within one week of randomization.~Women allocated to progesterone group will be receiving 200 mg vaginal progesterone, purchased from the manufacturer (Cyclogest® 200 mg, Actavis, United Kingdom), once daily at bedtime. They will be given a monitoring sheet and instructed to note everyday the date of using.~In case of premature rupture of membranes, active vaginal bleeding, other signs of preterm labor or severe patient discomfort, the pessary may be removed. If participants develop (threatened) preterm labor, they will receive treatment per local protocol. Intervention will be stopped at 370/7 weeks of gestation or at delivery.~Along side with this trial, another study will be conducted to determine how changes in peripheral blood and cervical inflammatory markers are impacted by progesterone versus pessary. Because of that, participants will be asked to take 5 ml blood sample and cervical-vaginal discharge sampling at the time of randomization, 4-8 weeks after randomization and before giving birth.~A cost-effectiveness analysis will also be conducted alongside this RCT. Data will be reported in a separated paper.
This study compares the effectiveness of cervical pessary to vaginal progesterone for prevention of preterm birth in women with singleton pregnancies and a cervix ≤25 mm.~Participants will be randomly assigned in a 1:1 ratio to receive cervical pessary or vaginal progesterone.