The viscoelastic properties of the cervical mucus plug

ObjectiveTo characterize the viscoelastic properties of cervical mucus plugs (CMPs) shed during labor at term. DesignExperimental research. SettingDepartment of Obstetrics and Gynecology, Aarhus University Hospital, Denmark. Population/SampleSpontaneously shed CMPs from 18 healthy women in active labor. MethodsViscoelastic properties of CMPs were investigated with a dynamic oscillatory rheometer using frequency and stress sweep experiments within the linear viscoelastic region. Main outcome measuresThe rheological variables obtained were as follows: elastic modulus (G), viscous modulus (G) and tan delta (G/G). Random-effects regression was used for statistical analysis. ResultsAll CMPs showed solid-like viscoelastic behavior. This was substantiated by the elastic modulus which was three to four times greater than the viscous modulus and by tan delta, which was