Tocolysis in the Management of Preterm Premature Rupture of Membranes Before 34 Weeks of Gestation

Inclusion Criteria: * Preterm premature rupture of membranes (PPROM) between 220/7 - 336/7 weeks of gestation, as diagnosed by obstetric team * Singleton gestation * Fetus alive at the time of randomization (reassuring fetal heart monitoring) * 18 years of age or older * French speaking * Affiliated to social security regime or an equivalent system * Informed consent and signed Exclusion Criteria: * PPROM ≥ 24 hours before diagnosis * Ongoing tocolytic treatment at the time of PPROM * Tocolytic treatment with Nifedipine between PPROM diagnosis and randomization * Fetal condition contraindicating expectant management including chorioamnionitis, placental abruption, intrauterine fetal demise, non-reassuring fetal heart rate at the time of randomization * Cervical dilation \> 5 cm * Iatrogenic rupture caused by amniocentesis or trophoblast biopsy * Major fetal anomaly * Maternal allergy or contra-indication to Nifedipine or placebo drug components\*: * Myocardial infarction * Unstable angina pectoris * Hepatic insufficiency * Cardiovascular shock * Beta blockers placebo drug components: lactose monohydrate, colloidal silica, microcrystalline cellulose * Coadministration of diltiazem or rifampicin * Hypotension (systolic pressure \< 90 mmHg) * Participation to another interventional research (category 1) in which intervention could interfere with TOCOPROM's results (efficacy and safety)