Pilot Study of Microvesicles in Pre-eclamptic and Non-pre-eclamptic Women With Threatened Preterm Delivery

Inclusion Criteria: * Age ≥ 18 years * Singleton pregnancy (or spontaneously reduced twin pregnancy before 14 SA) * Gestational age at inclusion between 23 and 31+6 SA * Collection of the patient's non-opposition * Affiliated or beneficiary of a social security system * Specifically for the non-pre-eclampsia group: non-pre-eclamptic patient hospitalized for isolated threat of preterm delivery, whatever the origin, and without clinical (absence of maternal hyperthermia defined by a maternal temperature \< 38.0°C) or biological markers of inflammation (CRP\<5) * Specifically for the pre-eclampsia group : diagnosis of severe pre-eclampsia before 32 weeks' gestation Exclusion Criteria: * Patient's inability to understand the nature, risks, meaning and implications of the clinical investigation or refusal to give consent * Patient under legal protection.