The aim is to assess the impact of tranexamic acid (TXA) for preventing postpartum hemorrhage (PPH) following a cesarean section (CS).

Regarding the prevention of PPH, recent randomized controlled trials (RCTs) of unclear quality have suggested that TXA may reduce blood loss and maternal morbidity, while a Cochrane Collaboration review has concluded, that "TXA (in addition to uterotonic medications) decreases postpartum blood loss and prevents PPH and blood transfusions following vaginal birth and CS in women at low risk of PPH based on studies of mixed quality. Further investigations are needed on efficacy and safety of this regimen for preventing PPH.

Treatment, that is a 10-mL blinded vial of the study drug (either 1g TXA or placebo according to the randomization sequence), will be administered intravenously to the participant women during the third stage of labor of cesarean delivery.

The follow-up visit will take place in the postpartum ward of the maternity unit, on D2 postpartum. This stage will include a venous blood sample to measure plasma concentrations of Hb and Ht, urea and creatinemia, prothrombin time (PT), active prothrombin time (aPTT), aspartate and alanine transaminase, total bilirubin and fibrinogen, and the completion of a self-questionnaire about satisfaction by the women, as well as the assessment of the adverse events.

At 8 weeks postpartum, a self-questionnaire assessing psychological status and well-being will be sent to the women. At 12 weeks postpartum, all participants will be contacted by phone to assess the incidence of thrombotic and any other significant events.

Inclusion Criteria:

• : adult women admitted for a cesarean delivery before or during labor, at a term ≥ 34 weeks,
• hemoglobin level at the last blood sample >9g/dl,
• available blood test for Hb and Ht within one week before caesarean delivery,
• informed signed consent

Exclusion Criteria:

• previous thrombotic event or preexisting pro-thrombotic disease,
• epileptic state or history of seizures,
• presence of any chronic or active cardiovascular disease outside hypertension,
• any chronic or active renal disease and chronic or active liver disease at risk thrombotic or hemorrhagic, autoimmune disease,
• sickle cell disease,
• placenta praevia,
• placenta accreta/increta/percreta,
• abruption placentae,
• eclampsia,
• HELLP syndrome,
• significant hemorrhage before cesarean section
• in utero fetal death,
• administration of low-molecular-weight heparin or antiplatelet agents during the week before delivery,
• planned general anesthesia,
• hypersensitivity to tranexamic acid or concentrated hydrochloric acid,
• instrumental extraction failure,
• multiple pregnancy with vaginal delivery of the first child,
• poor understanding of the French language.

Double blind