Induction of Labor in Patients With Unfavorable Cervical Conditions

Artificial ripening of the cervix and induction of labor remain as one of the therapeutic challenges in Obstetrics. The method widely used, the intravenous administration of Oxytocin, is associated with prolonged induction periods, a significant failure rate, and considerable patient discomfort. Therefore, over the years, a variety of locally applied pharmacological and physical ripening agents were evaluated. Currently, the commonly utilised local ripening agent is a Prostaglandin (PG) preparation. Although PG is being applied vaginally or extra-amniotically, systemic absorption of this agent is common, sometimes resulting in uterine hypertonicity, nausea and vomiting. In addition, both induction methods are associated with the initiation of uterine contractions, sometimes lasting for prolonged periods. Therefore a preferred induction method may be a mechanical one which will lead to cervical ripening without causing uterine contractions. Furthermore, there are additional potential advantages of mechanical methods compared to pharmacologic methods such as, ease of storage, low cost and less side effects. A folly catheter, inserted through the cervix, combined with continuous extra-amniotic NS instillation is being used for this purpose for many years. However this method although effective may cause uncomfortable traction of the balloon to the women's leg. Furthermore, dripping of saline through the cervix and vagina, occasionally occurs, may be annoying, and may be confused with rupture of membrane. We have recently introduced a newly developed balloon device (Atad Ripener Device), which was designed with one balloon located at the distal end of the device (the uterine balloon, U), while the other balloon is located 1.5 cm proximal to the first one (the cervicovaginal balloon, CV). Both balloons are expandable with Saline. The balloon inflated in the vagina provides the traction action and seals the cervix from saline leakage. Another balloon the AID (Atad double balloon Instillation Device) is identical to the ARD but has an additional long tip for instillation of normal to the extra-amniotic space. To the best of our knowledge, no comparison was performed between the use of the double balloon ripener device and folly catheter for induction of labor. Furthermore, there are no published data regarding the use of the double balloon instillation device (AID) combined with continuous extra-amniotic NS instillation. This study is designed to compare the efficacy, safety and side effects of mechanical methods of cervical ripening and labor induction by the double balloon device (ARD), the double balloon instillation device (AID) combined with continuous extra-amniotic instillation of normal saline and the folly catheter combined with continuous extra-amniotic normal saline instillation. The study aims at the accrual of 300 women (100 randomised in each arm).

Inclusion Criteria:

• Patients 15 years of age or older.
• Diagnosed to be pregnant with an indication for induction of labor.
• Having a Bishop score of 4 points or less.
• Diagnosed as having a singleton pregnancy in a vertex presentation, with intact membranes, and no significant regular uterine contraction at gestational age of >28 weeks.
• Willingness to comply with the protocol for the duration of the study.
• Have signed an informed consent.

Exclusion Criteria:

• Any contraindication for a vaginal delivery (i.e. placenta previa, non vertex presentation).
• Ruptured membranes.
• Previous cesarean section or any uterine scar.
• Documented labor.
• Suspected fetal distress necessitating immediate intervention.
• Proven malignancy of the cervix.
• Active inflammatory or purulent condition of the lower genital tract.