Reduction of Cesareans by Nitric Oxide (NO) Donors in Post Term Pregnancies (NOCETER)

• Number of labor inductions [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Number of spontaneous labors [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Cesarean for failed labor induction [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Cesarean for FHR abnormalities [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Cesarean for arrested labor [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Mean time between randomisation and spontaneous labor [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Isosorbide mononitrate adverse effects [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Maternal satisfaction [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Neonatal morbidity [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Mean time between randomisation and delivery [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Mean duration of labor [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]

• Number of labor inductions [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Number of spontaneous labors [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Cesarean for failed labor induction [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Cesarean for FHR abnormalities [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Cesarean for arrested labor [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Bishop score at 41+2, 41+4, and labor induction [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Isosorbide mononitrate adverse effects [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Maternal satisfaction [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]
• Neonatal morbidity [ Time Frame: 10 days ] [ Designated as safety issue: Yes ]

The purpose of this trial is to determine whether cervical ripening with isosorbide mononitrate reduce caesarean section in women with post term pregnancies.

The purpose of this trial is to determine whether cervical ripening with 40 mg of isosorbide mononitrate given intravaginally at 41+0, 41+2 and 41+4 weeks reduce cesarean section in nullipara with post term pregnancies. Treatments will be administered by midwifes in the maternity wards, women will be allowed to go back home in case of Bishop score<6. Otherwise labor will be induced with oxytocin. If undelivered at 41+5, women with Bishop score<6 will be induced with prostaglandins according to local protocols.

• Prolonged Pregnancy
• "Nulliparity"

• Drug: IMN
  Administration of 2 x 20 mg of isosorbide mononitrate at each administration with a maximum of three administrations
  Other Name: IMN
• Drug: Placebo
  Administration of 2 X 20 mg of placebo of IMN at each administration with a maximum of three administration
  Other Name: Placebo

• Experimental: IMN
  Isosorbide mononitrate
  Intervention: Drug: IMN
• Placebo Comparator: Placebo
  Administration of placebo of IMN
  Intervention: Drug: Placebo

Inclusion criteria :

• Age > or = 18 years old
• TAS > or = 95 mmHg
• Singleton
• Nulliparity
• Term > or = 41 weeks + 0 day
• Bishop score < or = 5
• Vertex presentation
• Intact membranes
• No contra-indications of the study treatment
• No maternal or fetal diseases which could indicate immediate labor induction
• Written informed consent

Exclusion criteria :

• Multiple pregnancy
• Multiparity
• Term < 41 weeks
• Bishop score > 5
• Breech presentation
• Rupture of the membranes
• Previous cesarean
• Indication to immediate labor induction
• Contraindications to isosorbide mononitrate
• No co-administration of antihypertensive drugs
• No social security