stylistic:tone
Epidemiology

During pregnancy and after childbirth, acute VTE occurs in about 1.2 of 1000 deliveries. Despite it being relatively rare, it is a leading cause of maternal morbidity and mortality. After surgery with preventive treatment, VTE develops in about 10 of 1000 people after total or partial knee replacement, and in about 5 of 1000 after total or partial hip replacement. About 400,000 Americans develop an initial VTE each year, with 100,000 deaths or more attributable to PE. Asian, Asian-American, Native American, and Hispanic individuals have a lower VTE risk than Whites or Blacks. Populations in Asia have VTE rates at 15 to 20% of what is seen in Western countries, with an increase in incidence seen over time. In North American and European populations, around 4–8% of people have a thrombophilia, most commonly factor V leiden and prothrombin G20210A. For populations in China, Japan, and Thailand, deficiences in protein S, protein C, and antithrombin predominate. Non-O blood type is present in around 50% of the general population and varies with ethnicity, and it is present in about 70% of those with VTE.