A novel aspiration technique to assess cervical remodelling in patients with or without cervical shortening: Sequence of first changes, definition of cut-off values and impact of cervical pessary, stratified for cervical length

Background The therapeutic significance of the cervical pessary has been confirmed by several studies. However, the underlying mechanism by which pessaries reduce the risk of a preterm birth remains elusive. The aim of this study is to investigate the hypothesis whether the application of a cervical pessary may stabilize the ectocervical stiffness in order to achieve a cervical arrest. Methods This is a prospective, controlled, non-interventional, post-market, monocentric, longitudinal, cohort study in a tertiary maternity hospital to determine ectocervical stiffness and its changes measured before and after placement of a pessary in singleton pregnancies with cervical shortening in the mid trimester. In order to assess reference values for cervical stiffness, we measured also singleton pregnancies with normal cervical length in the same gestational week spectrum. The cervical stiffness measured with the Pregnolia System as the Cervical Stiffness Index (CSI, in mbar) shall be the primary endpoint, whilst patient delivery data (gestational age, mode of delivery and complications) will be the secondary endpoint. In this pilot study, up to 142 subjects will be enrolled to have a total of 120 subjects (estimated dropout rate of 15%) to complete the study; pessary cohort: 60 (up to 71 recruited), control group: 60 (up to 71 recruited). Discussion Our hypothesis is that patients with cervical shortening will present with lower CSI values and that pessary placement will be able to stabilize the CSI values through further prevention of cervical remodelling. The measurement of controls with normal cervical length shall serve as a reference.