Pregnancy complicated with deficiency of antithrombin: Review of current literature

Antithrombin deficiency, although the rarest thrombophilia, carries the highest risk of thromboembolism. This risk is increased especially for pregnant women due to physiological coagulation changes in pregnancy. Therefore, in cases of positive personal and/or family history of thromboembolic events as well as recurrent pregnancy loss women should be tested for antithrombin deficiency. Antithrombin deficiency is caused by numerous mutations of serpin peptidase inhibitor clade C 1 gene (SERPINC) and is classified according to antithrombin plasma activity and antigen levels into Type I (quantitative defect) and Type II (qualitative defect). Complications during pregnancy can be divided into those regarding the mother and those concerning the fetus. The main clinical manifestation of antithrombin deficiency regarding the mother is thromboembolism occurring spontaneously or recurrently during pregnancy. Numerous major gestational complications such as miscarriage, intrauterine growth restriction or fetal death, placental abruption, preeclampsia and hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome can be linked to antithrombin deficiency. Close monitoring with early and adequate prophylaxis and treatment nowadays can mostly assure the positive pregnancy outcome for both mother and child. Prophylaxis/therapy with both low molecular weight heparin and antithrombin concentrate should start as soon as pregnancy is planned or at least as early as possible in pregnancy and continue until the end of the puerperium.