Sonographic assessment of the cervical length before induction of labor

ObjectiveTo compare the cervical length measured by TVS with modified Bishop's score for cervical assessment before induction of labor.MethodsOne hundred and twenty women in their first pregnancy were admitted for induction of labor. Digital vaginal examination was done to record the modified Bishop's score, followed by TVS to detect the cervical length. The method of induction of labor was decided after the initial vaginal examination, when the modified Bishop's score was evaluated. Dinoprostone pessary was used for labor induction if the Bishop score was < 5 (unfavourable cervix), and amniotomy was usually performed when the cervix was 3 cm dilated, and the presenting part was low (0 station).ResultsThe cervical length measured by TVS was significantly shorter in the patients delivered vaginally, compared with the patients delivered by cesarean section (24.7±6.9) versus (26.5±8.2) mm; respectively. A total of 72 (78.3%) of the patients delivered vaginally, and 10 (35.7%) of the patients delivered by cesarean section had cervical length < 25 mm. The modified Bishop's score was significantly high in the patients delivered vaginally, compared with the patients delivered by cesarean section (6.0±2.7) versus (5.9±8.7) respectively. Moreover, 77 (83.7%) of the patients delivered vaginally, and 11 (39.3%) of the patients delivered by cesarean section had modified Bishop's score > 5.ConclusionsBoth Methods of cervical assessment (cervical length measured by TVS, and modified Bishop's score) were significantly associated with successful induction.