The Effect of Dilute 0.25% Vasopressin Solution on the Linear Force Necessary for Cervical Dilatation

We assessed the force necessary for mechanical cervical dilatation on a nonpregnant uterus after intracervical administration of dilute vasopressin solution 0.05 U/ml. In a prospective, double-blind, randomized study, vasopressin or placebo was injected into the cervical stroma before dilating the cervix in preparation for resectoscopy. An electronic load cell was used to measure the peak linear force necessary to dilate the cervix from 3 to 11 mm using half-size metal dilators. Mean (± SEM) total peak linear force to dilate the placebo-treated cervix from 3 to 11 cm was 36.82 ± 1.88 lbs (range 6.11-52.2 lbs). In the vasopressin group it was 20.57 ± 5.54 lbs (range 5.54-40.82 lbs, p <0.001), a 44.1% reduction. One cervix (3.8%) in the placebo group and one (3.6%) in the vasopressin group required suturing of lacerations (p >0.05). This effect of dilute vasopressin solution may reduce trauma to the internal cervical os and lower uterine segment.