Vaginal progesterone vs cervical pessary in the first trimester of pregnancy for preventing preterm birth: a multicenter randomized clinical trial

Abstract

Background: Preterm birth has increased in the last decades and it has a lot of negative consequences not only for the new-borns, but also for their families and for the health system. Several studies found evidence about doing a vaginal ultrasonography in the mid-trimester of pregnancy to those women with risk factors of preterm birth to measure their cervix length. If the cervix is ≤25 mm, preventive treatment will be recommended. This treatment would be vaginal progesterone or a cervical pessary. Some studies showed that the measure of the cervix length could be done earlier because there is a relationship between the short cervix in the 2nd and sooner in the 1st trimester. Thus, the prevention could be done since the 1st trimester of pregnancy. Objective: To prove if the vaginal progesterone is a better preventive treatment than cervical pessary, both used since the 1st trimester of pregnancy, in those asymptomatic women with risk factors of prematurity, single gestations and a cervix length of ≤30 mm. Design and methods: It is a multicentre randomized clinical trial, including 900 pregnant women that will be recruited in five hospitals of Catalonia for 20 months. They will be randomized in two different groups: 450 women will receive vaginal progesterone, and a cervical pessary will be inserted in 450 women. We will collect the preterm birth rate in each group to do a statistical analysis and compare the percentages adjusted for all the co-variables. Participants: pregnant asymptomatic women, with single gestation, risk factors for preterm birth and a cervix length of ≤30 mm measured by vaginal ultrasound within 11- 13+6 weeks of gestation