The natural history of a positive response to transfundal pressure in women at risk for cervical incompetence

OBJECTIVE: Our purpose was to observe the evolution of the endocervical canal length in women at risk for cervical incompetence after a positive response to transfundal pressure. STUDY DESIGN: Ten women at risk for cervical incompetence had a midtrimester cervical evaluation with transvaginal ultrasonography and transfundal pressure. With a transvaginal probe, the endocervical canal length was first measured. Transfundal pressure was then applied and the endocervical canal length was remeasured. All patients had a positive response to transfundal pressure as defined by a decrease in endocervical canal length after application of transfundal pressure. At the initial evaluation the digital examination of the cervix had revealed a closed and long cervix in all 10 cases. In 9 of the 10 patients repeat examinations were performed until the endocervical canal length progressively shortened to