Background: Acute VTE occurs with an incidence of 1-2/1,000 during pregnancy and is associated with an acute mortality of 1-2%. However, data on VTE treatment during pregnancy are sparse: Even though 50 cases occur daily in the EU and US, a recent review identified only 174 cases in the literature.
Acute treatment: Standard treatment is LMWH at therapeutic doses or APTT-adjusted UFH. LMWH is at least as safe and effective as UFH in non-pregnant patients. In pregnancy, LMWH is the preferred option, because it offers better bioavailability, fewer injections, superior safety regarding HIT and osteoporosis. LONG-TERM TREATMENT: VKA are contraindicated because of teratogenicity and thus heparin is used for secondary prevention. Since UFH requires therapeutic doses throughout pregnancy, carrying the risk of osteoporosis, LMWH is the drug of choice. In a recent review most patients were treated initially with LMWH, predominately with twice daily injections. Recurrent VTE occurred in 1.2%, bleeding in 1.7%, with no HIT. Whether the long-term dose of LMWH can be reduced remains unresolved: Intermediate dose LMWH has been used effectively in cancer patients, who - like pregnant women - continue to have a high pro-thrombotic burden after the initial phase.
Conclusion: Even though acute VTE is not uncommon and represents a life-threatening event during pregnancy, data are sparse, and prospective trial data are needed to answer open questions concerning treatment modalities. Nevertheless, it is evident that LMWH is the preferred option for treatment of VTE during pregnancy.