[Thrombophilia and pregnancy: who should be tested? Which tests should be performed? The biologist point of view].

Pregnancy is associated with an increased risk of venous thromboembolism, especially in women with a congenital predisposition. The detection of these thrombophilias, with an autosomal dominant transmission, is justified if an appropriate prophylaxis is administered during pregnancy and/or post-partum. The aim of the prophylaxis is to prevent thrombotic events and possibly adverse pregnancy complications, such as pregnancy loss at the second or third trimester, intra-uterine fetal growth retardation or pre-eclampsia. The magnitude of the pregnancy-associated risk in the different thrombophilias is taken into account for the selection of the patients to be tested for the detection of thrombophilia. Tests to be performed are proposed and their interpretation depends on whether the patient is pregnant, receiving oral contraception or oral anticoagulants.