Intravaginal saline as a contrast agent for cervical sonography in the obstetric patient.

Abstract

To determine whether intravaginal saline alters visualization of the cervix during endovaginal sonographic examinations. A prospective trial with comparison of sonographic measurements of cervical length prior to and after administration of an intravaginal contrast agent. Patients with an indication for endovaginal ultrasonographic assessment of the cervix were considered as candidates for the study. After assessment of cervical dimensions and contour of the internal cervical os, 10 ml of normal saline was placed intravaginally via a needleless syringe. Pre- and post-contrast sonographic examinations of the cervix were compared. Twenty-six patients were enrolled. No differences were observed in the identification of funnelling (37% in each group, p = 1.0) or the quantification of cervical length for the entire cohort (p = 0.95). However, in a subset of patients in whom the external os was not satisfactorily visualized (23%), intravaginal contrast resulted in a mean difference in cervical length pre- and post-saline infusion of 6.4 mm compared to 1.4 mm in patients in whom the external os could be easily identified (p < 0.001). No patient expressed undue discomfort related to the administration of contrast. Intravaginal saline assists in visualization of the cervix during endovaginal sonography for selected patients in whom precise identification of the external os is difficult.