Among all patients hospitalized for Threatened Premature Delivery (TPD), the rate of premature birth (PB) before 37 weeks is about 42%, which reflects the inability to accurately identify patients at high risk of PB. Currently, no clinical or biological marker is recognized as the most reliable in predicting the real risk of AP in case of MAP.

The purpose of this study is to improve the knowledge of predictors of preterm delivery compared with conventional blood markers by estimating serum procalcitonin according to premature delivery or not in patients hospitalized for preterm labor .

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