Prominent cervical mucous and its impact on cervical length measurement: findings of a national survey

Introduction: Cervical length measurement by transvaginal scanning (TVS) has been proposed by some as a universal screening test for preterm labour. The presence of prominent cervical mucous may affect assessment of the cervix; however, the exact technique to measure the cervix when there is prominent mucous or funnelling has not been described. We evaluated the level of agreement in cervical length measurements amongst Australian specialists and sonographers reporting on cervical assessment using an online survey.

Methods: We conducted an online survey with 11 images of the cervix to assess how obstetric sonographers and sonologists report on the cervix when there is prominent mucous or funnelling. They were asked five questions about the image of the cervix. A kappa coefficient was calculated from the responses.

Results: We had 151 complete responses to the online survey. For the images which showed funnelling or prominent cervical mucous, there was little agreement regarding the cervix being open or closed and regards the location of the internal os. The Kappa coefficient was 0.22 indicating a low level of agreement for the location of the internal os.

Conclusion: There is lack of agreement amongst Australian specialists and sonographers reporting on cervical assessment when there is prominent mucous or funnelling seen in the cervix. We propose a method to standardise reporting on the cervix incorporating the chorioamniotic membrane for the identification of the inner cervical os when there is prominent mucous or funnelling.