Premature birth is a public health problem and its incidence has recently increased in all developed countries. In Canada, it represented 6.4% of births in 1981 and 7.6% in 2000. In the last decade, the survival rate of premature infants has increased considerably, but neurological vulnerability has not changed. Premature births are the cause of approximately 28% of neonatal mortality in the world and is the major cause of perinatal mortality and morbidity in developed countries.

Approximately 75-80% of preterm births are spontaneous preterm birth. This type of premature birth included the preterm labor and premature rupture of membranes before term. The contractile activity represents one of the fundamental properties of the uterus during pregnancy and childbirth. The abnormalities associated with uterine contractions are the cause of pathological conditions with important consequences for the mother and fetus.

Metabolomics involves a new technology to investigate small molecules that characterize biochemical pathways of interest. The change in concentration levels of these molecules in various biological samples such as urine and blood in the presence of a disease or a patient can be particularly useful for identifying new biomarkers.

The hypothesis of this study is that gestational metabolomes detected in maternal fluids differ according to pathological situations and lead to the initiation of spontaneous labor. The whole research program has two complementary objectives in order to expect a decrease of prematurity: a) better understanding of all the physiological mechanisms leading to prematurity and b) better identification of patients at high risk for a better management of these women.

Metabolomics involves a new technology using the methods of separation and detection complex to investigate a set of small molecules that characterize biochemical pathways of interest. The change in concentration levels of these molecules in various biological samples such as urine and blood in the presence of a disease or a patient can detect metabolic fingerprints that can be particularly useful for identifying new biomarkers. These will thereafter be quantified and validated by metabolic profiling. To our knowledge, there are few studies on metabolomics and pregnancy.

Methods:

The studied population will be pregnant women between 20-30 weeks of gestation without any obstetrical complications.

Vaginal secretions, blood and urine samples will be taken:

• After inclusion in the project
• At hospital admission for delivery
• During labor

Blood and urine sample will also be taken:

• 48 hours after delivery
• 6-8 weeks after delivery

Inclusion Criteria:

• Women with single pregnancy
• Adults (> 18 years old)

Exclusion Criteria:

• Women with a severe congenital fetal malformation
• Fetal death
• Preexisting hypertension (ie before 20 weeks of gestation)
• Anti-phospholipid syndrome
• Lupus,
• Nephropathy, etc.
• Viral infections (HIV or hepatitis)
• Women who want an elective Caesarean section are excluded

Pregnant women between 20-30 weeks of gestation who have a low risk pregnancy.