The aim of the study is to evaluate haemostasis and fibrinolysis in peripartum of caesarean delivery and the effect of tranexamic acid (TXA) given in prevention of post-partum haemorrhage (PPH).

Post-partum haemorrhage (PPH) remains a leading cause of maternal morbidity and mortality. Haemostasis and fibrinolysis are activated in peripartum. Fibrinolysis is decreased during pregnancy, is quickly activated after childbirth and can be overactivated in case of PPH. Tranexamic acid (TXA), an antifibrinolytic drug, has been proven to efficiently decrease bleeding and death in PPH. Its place in prevention of PPH after caesarean section remains to be established. The aim of the study protocol TRAAP2 is to conduct a large multicentre randomized, double blind placebo-controlled trial to adequately assess the impact of TXA for preventing PPH following a caesarean section. Peripartum is also a period of increased thrombo-embolic risk. TXA has never been proven to increase thromboembolic events. Nevertheless, it seems important to reserve TXA for women with activated fibrinolysis.

The aim of the ancillary biologic study BIO-TRAAP is thus to explore haemostasis and fibrinolysis in peripartum, to determine which women will in the future benefit from TXA. Fibrinolysis will be studied by clot lysis time by Global Fibrinolytic Capacity test on the Lysis Timer (GFC/LT), t-PA, PAI-1, PAI-2, euglobulin clot lysis time, plasminogen, plasmin-anti-plasmin complex, thrombin-anti-thrombin complex, fibrin degradation products (FDP).

Inclusion Criteria:

• patient randomized into TRAAP2 study (NCT03431805):

  • adult women admitted for a planned caesarean delivery,
  • at term ≥ 34 weeks,
  • haemoglobin level at the last blood sample >9g/dl,
  • blood Formula numbering within 7 days before caesarean delivery, informed signed consent)

• informed signed consent for BIO-TRAAP

Exclusion Criteria:

• patient not included into TRAAP2 study:

  • previous thrombotic event or pre-existing 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 including renal, chronic or acute insufficiency (glomerular flow <90mL / min), and chronic or active liver disease at risk thrombotic or haemorrhagic,
  • autoimmune disease,
  • sickle cell disease,
  • placenta praevia,
  • placenta accreta/increta/percreta,
  • abruption placentae,
  • eclampsia,
  • HELLP syndrome,
  • in utero fetal death,
  • administration of low-molecular-weight heparin or antiplatelet agents during the week before delivery,
  • general anaesthesia,
  • hypersensitivity to tranexamic acid or concentrated hydrochloric acid, instrumental extraction failure,
  • multiple pregnancy with genital delivery of the first twin and caesarean delivery for the second or at third trimester,
  • poor understanding of the French language

Double blind