Background: Previous estimates of the rate of recurrent venous thromboembolism (VTE) during pregnancy in women with a history of VTE have vary between 0 and 13%. Therefore, the decision to administer or withhold heparin - especially in the antepartum period - has been discussed controversial. In a recent study by

Brill-Edwards et al. (N Engl J Med 2000;343:1439–44)
, no recurrences of VTE occurred in women (n=44) who had a previous episode of thrombosis that was associated with a temporary risk factor and who also had no evidence of thrombophilia. Based on these results, antepartum heparin prophylaxis is not routinely recommended in women without thrombophilia whose previous episode of thrombosis was associated with a temporary risk factor (ACCP guidelines 2004). The objective of our study was to evaluate the risk of recurrent pregnancy-associated thrombosis in women with a history of VTE.

Materials and Methods: We retrospectively studied 198 women with at least one pregnancy (275 pregnancies in total) after a one previous episode of VTE. Sixty-three women (81 pregnancies) were excluded from the analysis because of antepartum heparin prophylaxis.

Results: In the subgroup of women without heparin prophylaxis (n=135), 15 (7.7%) thromboembolic events occurred antepartum in 194 pregnancies. Further subgroup analysis, stratified for the nature of first VTE, gave the following number of antepartum VTE per number of pregnancies: 2 VTE/19 pregnancies (10.5%) in 14 women (first VTE: immobilization), 4 VTE/33 pregnancies (12.1%) in 24 women (first VTE: surgery), 5 VTE/69 pregnancies (7.2%) in 46 women (first VTE: oral contraception), 2 VTE/58 pregnancies (3.4%) in 40 women (first VTE: pregnancy), 2 VTE/15 pregnancies (13%) in 11 women (first VTE: idiopathic). Nine of the 15 women with VTE (7/13 women with first VTE triggered by temporary risk factor; 2/2 women with first idiopathic VTE) had a heterozygous factor V Leiden G1691A or prothrombin G20210A gene mutation. In the postpartum period, 16 VTE in 194 pregnancies occurred after live birth in the 135 women without heparin prophylaxis. Nine of these 16 women had a heterozygous FVL or prothrombin G20210A gene mutation. In Conclusion, the risk of recurrent antepartum VTE was similar in women with and without factor V Leiden G1691A or the prothrombin G20210A gene mutation and did not differ between women with first VTE triggered by a transient risk factor or an idiopathic first VTE. In addition to recommended postpartum heparin prophylaxis, our data support the need for a routine antepartum prophylaxis in women without thrombophilia whose previous episode of thrombosis was associated with a temporary risk factor.

Topics:
oral contraceptives, pregnancy, thrombosis, venous thromboembolism, heparin, thrombophilia, factor v leiden, brill's disease, immobilization, surgical procedures, operative

Disclosure: No relevant conflicts of interest to declare.

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2006, The American Society of Hematology
2006
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