A Phase 3B, Multi-Center, Randomized, Double-Blind Study of Hydroxyprogesterone Caproate Injection, 250 mg/mL, Versus Vehicle for the Prevention of Preterm Birth in Women with a Previous Singleton Spontaneous Preterm Delivery - ND

INTERVENTION: Product Name: Idrossiprogesterone Caproato Product Code: 17P Pharmaceutical Form: Solution for injection CAS Number: 630‐56‐08 Current Sponsor code: 17P Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 250‐ Pharmaceutical form of the placebo: Solution for injection Route of administration of the placebo: Intramuscular use CONDITION: Preterm birth ; MedDRA version: 9.1 Level: LLT Classification code 10036594 PRIMARY OUTCOME: Main Objective: The primary objective of this study is to determine if treatment with 17P reduces the rate of preterm birth < 350 weeks of gestation in women with a singleton pregnancy, aged 18 years or older, with a previous singleton spontaneous preterm delivery. Primary end point(s): The primary efficacy outcome is preterm birth prior to 350 weeks of gestaion as determined by project gestational age, which will be evaluated in a standardized manner. Secondary Objective: The secondary objectives of this study are to:; Determine if 17P reduces the rate of neonatal mortality or morbidity, if and only if, the rate of preterm birth < 350 weeks of gestation is statistically significant (i.e., hierarchical testing approach). Neonatal mortality or morbidity is measured by a composite index comprised of ; o Neonatal death.; o Grade 3 or 4 intraventricular hemorrhage.; o Respiratory distress syndrome.; o Bronchopulmonary dysplasia.; o Necrotizing enterocolitis.; o Proven sepsis.; Exclude a doubling of the risk of fetal/early infant death, defined as spontaneous abortion/miscarriage (delivery from 160 through 196 weeks of gestation) or death (from minutes after birth until 28 days of life) occurring in liveborns born at less than 24 weeks gestation or stillbirth (antepartum or intrapartum death from 20 weeks gestation through term), in the 17P group compared to the vehicle group.; Determine if 17P reduces the rate of preterm birth < 320 weeks of gestatio INCLUSION CRITERIA: 1. Age ≥ 18 years. 2. Singleton gestation. 3. Project gestational age 160 weeks of gestation or more and less than or equal to 206 weeks of gestation at the time of randomization, based on clinical information and evaluation of the first ultrasound. 4. Documented history of a previous singleton spontaneous preterm delivery. Spontaneous preterm birth is defined as delivery from 200 to 366 weeks of gestation following spontaneous preterm labor or pPROM. Where possible, the gestational age of the previous preterm birth (referred to as the qualifying delivery) should be determined as described in Gestational Age Determination below. If the gestational age at delivery is obtained directly from the medical record and more than one gestational age appears, the latest will be used. As a validation of the gestational age of the previous delivery, if the infant weighed more than 3300 grams (the birth weight 90th percentile for 36 weeks gestational age), thi