Vaginal PROgesterone as Maintenance Treatment After an epISode of prEterm Labor (PROMISE Study)

• Median time from randomization to delivery [ Time Frame: delivery ] [ Designated as safety issue: No ]
• Ultrasound cervical length [ Time Frame: week +5 ] [ Designated as safety issue: No ]

• Median time from randomisation to delivery [ Time Frame: delivery ] [ Designated as safety issue: No ]
• Ultrasound cervical length [ Time Frame: week +5 ] [ Designated as safety issue: No ]

Eligible patients will be informed and asked to enroll in the study at hospital admission. A transvaginal ultrasound examination will be performed to determine cervical length. If an eligible woman accepts to participate, patient will be randomized to one of the study arms assigned in a double blind basis. Patient will receive the medication (vaginal capsule of progesterone or placebo). The patient will administer herself one vaginal capsule in a daily basis since gestational age of 36 weeks and 6 days as the primary endpoint is to demonstrate that the use of a maintenance treatment with vaginal progesterone is able to reduce the incidence of preterm birth before 34.0 and 37.0 gestational weeks. After delivery, perinatal and neonatal data will be collected.

• Drug: Progesterone
  1 vaginal capsule, 200 mg, once daily since gestation age 36 weeks and 6 days
• Drug: Placebo
  1 vaginal capsule, once daily since gestational age of 36 weeks and 6 days

• Active Comparator: A
  Progesterone 200 mg
  Intervention: Drug: Progesterone
• Placebo Comparator: B
  Placebo
  Intervention: Drug: Placebo

Inclusion Criteria:

• Pregnant women aged between 18 - 45 years
• Gestational age between 24.0 and before 33.6 gestational weeks
• Singleton pregnancy
• Patients admitted because of preterm labor who have been successfully treated of any tocolytic drugs (β-mimetics drugs, nifedipine, atosiban)
• Ultrasound cervical length at discharge < 25 mm
• Signed patient consent form (CI)

Exclusion Criteria:

• Known or suspected infection, premature rupture of membranes or any other pathological gravid maternal or fetal condition coexisting at hospital admission (Pre-eclampsia, RCIU) which may induce iatrogenic labor.
• Present or previous liver disease, present or previous cholestasis gravidarum, abnormal hepatic blood tests.
• With known allergy to progesterone or peanuts (excipient).
• Grade 2 (or upper) renal or liver laboratory abnormalities
• Treated from dependent-hormone malignant cancer (i.e., breast carcinoma...)
• With Diabetes mellitus or insulinized gestational diabetes
• Treated with heparin
• Drug abuse
• Inadequate treatment compliance