Pregnancy Failure and Heritable Thrombophilia
Section snippets
Definition of Pregnancy Failure
The various forms of pregnancy failure have not been defined consistently. Recently, a revision of the nomenclature of early pregnancy events was proposed that applies ultrasound imaging for accurate clinical assessment and diagnosis.17 Fetal loss is defined as the previous identification of crown-rump length and fetal heart activity followed by loss of heart activity. Recurrent miscarriage is defined as three early consecutive losses or two late pregnancy losses. Early miscarriage comprises
Antiphospholipid Antibody Syndrome
In women with recurrent miscarriage due to the antiphospholipid antibody syndrome, a landmark randomized controlled trial showed an absolute increase of live birth rate from 41% to 72% with the use of a combination of low-dose unfractionated heparin and low-dose aspirin, as compared to aspirin alone.31 A second randomized trial in which low-molecular-weight heparin was added to aspirin did not demonstrate benefit of this combination therapy, with live birth rates of 72% and 78% in both
Conclusions
Pregnancy failure and other vascular pregnancy complications are associated with the presence of acquired or heritable thrombophilia. Pathogenic mechanisms are likely to include effects on trophoblast differentiation and not solely hypercoagulability. Current guidelines recommend a combination of low doses of aspirin and heparin in women with antiphospholipid syndrome and recurrent fetal loss, although these are not based on a wealth of high-quality evidence. For women with heritable
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