Anticoagulation in pregnancy and puerperium: With a focus on the benefits and risks of the applications of vitamin K antagonists on the prevention of mechanical heart valves thrombosis

Introduction: The current number of women in the reproductive phase (from 15 to 45 years) in Europe is estimated at about 105 million, with about 5 million children annually born in average. About 1% of pregnancies among women in Europe are complicated by heart disease, the risk of cardiovascular disease in pregnant women being further increased by the fact that ever older women are giving birth. Methods: Preparing this paper is based on a systematic PubMed search of existing professional databases and accessible medical journals and textbooks dealing with this subject matter. Topic: Being certainly drugs with the best anticoagulant effect in situations of high risk for thrombosis, especially in patients with mechanical prosthetic heart valves during pregnancy, vitamin K antagonists (VKA) on the other hand also entail a well-known dose-related risk of embryo toxicity, genotoxicity, and hemorrhage in the fetus and in the mother. The choice of appropriate anticoagulant depends on the stage of pregnancy. In accordance with the North-American guidelines (American College of Chest Physicians - ACCP) for women already on oral vitamin K antagonists actively trying to conceive frequent pregnancy tests, and substitution of VKA with heparin drugs when pregnant are recommended rather than VKA replacement with low molecular weight heparin (Low Molecular Weight Heparin - LMWH) when planning a pregnancy. Heparin derivatives have no embryo toxic and fetotoxic characteristic effects of VKA but they are less effective at preventing valve thrombosis, due to which they have recently been superseded by improved techniques for monitoring effects of heparin, with a mentioned made that low molecular weight heparin used in high therapeutic doses requires obligatory (on a weekly basis) monitoring of anti-factor Xa coagulation activities. Conclusion: Adequate anticoagulant therapy during pregnancy requires an analysis of risk factors for thrombosis, hemorrhage risk, consideration of comorbidities in pregnant women, especially renal function, especially taking into account the gestational age. Though it must be admitted that there is no absolutely safe anticoagulant therapy during pregnancy, a choice of the safest option regarding the stated risks for the mother and the child is of paramount importance.