Intermediate-Dose Versus Low-Dose Low-Molecular-Weight Heparin in Pregnant and Post-Partum Women with a History of Venous Thromboembolism (Highlow Study): An Open-Label, Multicentre, Randomised, Controlled Trial

Venous thromboembolism (VTE) in pregnancy is a major cause of maternal morbidity and mortality, but its prevention, medical thromboprophylaxis, can bleeding complications. Without up to 10% women with history VTE are at risk pregnancy-related recurrence. For those who not on long-term anticoagulation medication, guidelines recommend subcutaneous low-molecular-weight heparin (LMWH) all the postpartum stage. moderate or high recurrent VTE, antepartum thromboprophylaxis recommended. In both cases, optimal dose unknown, professional societies do provide clear specific guidance often recommending multiple different dosing approaches without evidence guide recommendations. The aim this study was assess efficacy safety low- versus intermediate-dose LMWH pregnant VTE. This an open-label, randomized controlled conducted 70 hospitals Netherlands, France, Belgium, Norway, Demark, Canada, United States, Russia. Included were adult objectively confirmed either unprovoked provoked by hormonal minor factors, gestational age ≤14 weeks. Excluded previous related factor, indication for therapeutic-dose anticoagulants, contraindication LMWH. Eligible randomly assigned receive weight-adjusted fixed, low-dose heparin. Participants self-administered their allocated once daily participated in-person telephone contacts 2 weeks after randomization; 20 30 gestation; 1 week, 6 weeks, 3 months postpartum. primary outcome symptomatic bleeding. A total 1110 included analysis—555 group 555 group. Approximately 81% had hormone use, pregnancy, period. From randomization postpartum, occurred 2% 3% (relative risk, 0.69; 95% confidence interval, 0.32–1.47; P = 0.33). Antepartum 1% each treatment group; These findings remained consistent 4% 1.16; 0.65–2.09; p 0.63). <1% Early Last none comparing weight-adjusted, LMWH, similar periods. Moreover, no differences observed occurrence between groups. evidence-based that appropriate preventing