Procalcitonin and Threatened Premature Delivery

Inclusion Criteria: * age \> 18 year * Ongoing pregnancy with a start date of pregnancy known and confirmed by an ultrasound of the 1st Quarter performed between 10 and 14 weeks with a measurement of the crown-rump length * hospitalization for preterm labor between 24 and 36 weeks of gestation * Intact membranes, * not opposed to participate in the study Exclusion Criteria: * Pregnancy uncertain term (no early ultrasound) * Pregnancy combining a condition that can interfere with the assays performed, * Uterine malformation known * Multiple pregnancy, * Premature rupture of membranes, * Chrorio-amnionitis, * Fetal malformation known * Strapping * GB\> 15000 and CRP\> 10 mg / L, * No affiliation to a social security scheme. * Woman with a measure of legal protection