Estimated number of asymptomatic thrombophilic women who should use LMWH prophylaxis during pregnancy and/or the postpartum period to prevent pregnancy-related VTE, and estimated number needed to test
n/a indicates not applicable.
*Antepartum and postpartum combined.
†These estimates apply to women with a positive family history of VTE and assume an unrealistic 100% efficacy of prophylaxis with LMWH.
‡Based on family studies as outlined in Table 2.
§Based on a population risk of pregnancy-related VTE of 0.5% per pregnancy22 and a relative risk of 2 of VTE by having a positive family history.14