Increasing cesarean rate in France is worrying. Different methods are described for ripening labor : the use of prostaglandins is described but maybe dangerous for patients with scarred uterus and is not recommended.

Intracervical balloon is an efficient alternative methods which as already been tested for unfavorable cervix ripening on nulliparous women.

But it was rarely tested on women with scared uterus and unfavorable cervix (bishop score <4).

The investigators propose a prospective randomised trial comparing cervix ripening with intracervical balloon inflated by 50 ml sterile water during 12 hours versus ocytocin (reference method).

The investigators expect to demonstrate what it's a safe method to increase vaginal delivery for women with previous cesarean section who need an induction of labour.

Inclusion Criteria:

• Pregnancy over 37 weeks
• Singleton pregnancy
• Vertex presentation
• Previous caesarean section with unique Transversal segmentary incision
• Medical indication of induction of labor
• Unfavorable cervix with Bishop score < 4
• No Premature Rupture Of Membranes
• Informed consent

Exclusion Criteria:

• Before 18 years old
• Placenta Praevia
• Premature Rupture Of Membranes
• Uterine scar other than transversal segmentary incision
• Cervical infection (except Streptoccoccus Agalactiae carrier) or choriamnionitis
• Multiple pregnancy
• Fetal malpresentation
• Cesarean indication
• Latex allergy
• No informed consent