Mechanical properties of the pregnant human uterine cervix use of an instrument to measure the index of cervical distensibility.

An instrument has been designed and manufactured to measure precisely in clinical practice the distensibility index of the human uterine cervix expressed as centimeters per kilogram. Operation of the instrument and possible errors measuring the cervical distensibility index in nonpregnant patients, during gestation and during the postpartum period, are presented. The ability to easily quantify the mechanical characteristics of the uterine cervix in humans throughout gestation will now allow one to carry out precise studies concerning pharmacologically induced cervical maturation or pathological modifications of the uterine cervix in cervical incompetence or threatened premature labor.