BACKGROUND AND OBJECTIVE: Cervical ripening plays a pivotal role in successful induction of labor. Considering the importance of vaginal delivery, numerous methods have been proposed to ripen the cervix before proceeding with labor induction. This study aimed to compare the effects of transcervical catheter, Laminaria, and Isosorbide mononitrate on cervical ripening.

METHODS: This clinical study was conducted at Kosar Teaching Hospital of Qazvin, Iran on 75 singleton nulliparous women with gestational age of ≥39 weeks and Bishop score of less than four. Participants were randomly divided into three groups of transcervical catheter, Laminaria, and isosorbide mononitrate. In the first group, oxytocin was administered after the spontaneous discharge of catheter, and immediately after obtaining the Bishop score of >4 in the other groups. The following parameters were recorded and compared between the study groups: interval between the time of labor induction and cervical ripening, Bishop score at the time of induction, interval between oxytocin administration and full cervical dilation, duration of the second and third labor phases, mode of delivery, and maternal and neonatal complications (IRCT: 2014012616368N1).

FINDINGS: In this study, mean duration of cervical ripening was 150±42.42 minutes in the catheter group, 337.77±99.38 minutes in the Laminaria group, and 732.63±105.03 minutes in the isosorbide mononitrate group (p=0.001). Bishop scores at the time of labor induction and during the interval between induction and full cervical dilation were significantly lower in the transcervical catheter group (p=0.001). Moreover, no significant differences were observed between the study groups in terms of the duration of the second and third labor phases, mode of delivery, and maternal and neonatal complications.

CONCLUSION: According to results of this study, use of transcervical catheter led to the improvement of the Bishop score and reduced length of labor phases.