Determination of Reference Values for Diluted Russell's Viper Venom Time (dRVVT) Specific to Pregnant Women (GRAPL)

Study Overview
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Brief Summary
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Pregnancy is associated with significant changes in several aspects of haemostasis, especially an imbalance between procoagulant and anticoagulant factors. These changes contribute to creating a state of hypercoagulability, mainly at the end of pregnancy and during the post-partum period, protecting pregnant women from delivery haemorrhage, but exposing them to a major thromboembolic risk. Vascular diseases of pregnancy (VDP) are obstetric diseases which are linked to an ischaemic origin associated with placental thrombosis. These include pre-eclampsia, retroplacental haematoma, intrauterine growth retardation and even foetal death in utero. A number of risk factors have been identified for these VDPs, some of which have extremely serious consequences, the main one being antiphospholipid syndrome (APS). The diagnosis of VDP in a current or previous pregnancy requires close monitoring and joint management by an obstetrician, haemostasis physician, internist and medical biologist, particularly in terms of pre, peri- and post-partum anticoagulation in patients at increased risk of thromboembolism. The aim of treating APS during pregnancy is : to reduce the occurrence of maternal arterial or venous thrombotic complications in one hand and in the other hand to reduce the occurrence of obstetric complications, which are responsible of a significant morbimortality rate. The detection of a possible APS during pregnancy will therefore determine the specific management of patients. The latest guidelines from the Groupe Français d'Etude sur l'Hémostase et la Thrombose (GFHT) in 2022 recommended a diluted Russell's viper venom time (dRVVT) and an activated partial thromboplastin time (APTT) measured using a sensitive reagent such as silica (SCT) should be used to assess the presence of LA.

Detailed Description
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Official Title
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Thrombophilia Assessment and Pregnancy: Determination of Reference Values for dRVVT in Pregnant Women

Conditions
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Normal Pregnancy

Intervention / Treatment
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* Other: dosage dRVVT


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Control group : patients with normal pregnancies at the HCL. Affiliation to a social security regime Case group : Patients followed at the HCL who had an increased dRVVT ratio during pregnancy, investigated as part of the development of VDP during pregnancy. Affiliation to a social security regime Exclusion Criteria: History of thromboembolic disease History of autoimmune disease History of VDP

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| cases<br>Patients treated at HCL who have had an increased dRVVT ratio during pregnancy, investigated in the context of the development of VDP during pregnancy | Other: dosage dRVVT<br>* Blood test dRVVT assay on two tubes of blood in the haemostasis laboratory of the Center de Biologie et de Pathologie Est<br>|
| Controls<br>Patients with normal pregnancies followed at the Croix Rousse maternity hospital | Other: dosage dRVVT<br>* Blood test dRVVT assay on two tubes of blood in the haemostasis laboratory of the Center de Biologie et de Pathologie Est<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| dRVVT value during pregnancy. | Carrying out the dRVVT in the haemostasis laboratory of the Centre de Biologie et de Pathologie Est | through study completion, an average of 9 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Pregnancy, Thrombophilia, Antiphospholipid syndrome, Vascular diseases of pregnancy, Diluted Russell viper venom time