The investigators aim to evaluate the effect of administering papaverine prior to PGE2 insertion on changes in Bishop-scores and on the induction-to-delivery interval.

Researchers will compare drug papaverine to a placebo

More than 22% of all pregnant women undergo induction of labor. Induction of labor is usually medically indicated for maternal and fetal related conditions; however, elective induction has become more common since the ARRIVE trial. Women with an unfavourable cervix, according to Bishop-score (<6), are prone to higher induction failure rates and are candidates for cervical ripening.

The cervix is composed of connective tissue and smooth-muscle located mainly beneath the internal os. Papaverine is an antispasmodic-musculotropic drug that targets smooth-muscle, resulting in decreased muscle spasm and subsequent smooth-muscle relaxation. The half-life of the drug is in the range of 0.5-2 hours, and its action starts 10 minutes after administration. Short-term use of papaverine during the first trimester has been reported as safe. However, outcome data are lacking of the use of mucosotropic-agents prior to PGE2 (propess) insertion. We will investigate this in a trial in which the co-primary outcomes were the change in Bishop-score after PGE2 extraction and the PGE2 insertion-to-delivery interval

Inclusion Criteria:

• singleton term pregnancy
• bishop score
• need for labor induction with PGE2
• vertex presentation
• viable fetus

Exclusion Criteria:

• Prelabour rupture of membrane
• Twins pregnancy
• previous cesarean section
• allergy to the study medication
• fetal anomaly contraindications for vaginal delivery
• maternal supraventricular tachicardia

pregnant women

The authors are willing to share the data of the study upon request of the Editors.

The group allocation will be double blind. The randomization table will be available only to one member of the study, who will prepare the medications according to the allocated intervention. Participants will receive intravenous 0.9% normal saline with or without papaverine. The same bottles of normal saline will be use for the papaverine and placebo groups. Accordingly, the participants will be masked for the intervention. The participants, the researchers including the obstetricians who inserted the PGE2 (propess), the caregiver nurse who administrated the medication, the data collector, and the statistician will be blinded to the group allocations throughout the study