[Does the asymptomatic carriage of FV Leiden and FII prothrombin in heterozygous configuration represent the increased risk of thrombembolic complications during pregnancy, childbirth and postpartum?].

OBJECTIVE

To evaluate the course of pregnancy and puerperium in asymptomatic carriers of FV Leiden and FII prothrombin mutation in heterozygous configuration in terms of risk of thrombembolic disease and late pregnancy complications. To evaluate whether global prophylactic LMWH administration already during pregnancy has brought some benefit to these women.

TYPE OF STUDY

Prospective study.

METHODS

From June 2007 to June 2011, we monitored the incidence of thrombembolic events (TED) and severe late pregnancy complications in 473 asymptomatic carriers of FV Leiden and FII prothrombin mutation in heterozygous configuration. We also compared the ongoing changes of commonly clinically available hemocoagulation tests. In selected women, we added to coagulation tests a thrombin generation test (TGA) and thrombin-antithrombin test (TAT). In 253 women (Group A), preventive LMWH application was introduced already during pregnancy. In 220 women (Group B), the application of LMWH was commenced as late as on the delivery day. In both groups application of LMWH continued during the puerperium.

RESULTS

The incidence of TED in the whole group of carriers of thrombophylic mutations accounted for 0.19%. The incidence of severe late pregnancy complications was very low - 3%. Medians of the monitored parameters of the hemocoagulation in compared groups and 'healthy' controls did not show statistically significant differences at any stage of pregnancy, labor or end of puerperium, with the exception of the results of TAT test at the end of puerperium.

CONCLUSIONS

No direct causal relationship has been established between asymptomatic carriage of Leiden and prothrombin mutation in heterozygous configuration and the occurrence of severe late pregnancy complications. These types of mutation represent only a slightly increased risk in terms of development of thrombophylic events. General LMWH prophylaxis during pregnancy is not indicated. However, individual careful monitoring of hemocoagulation changes and early detection of associated transient situations potentiating risk of thrombembolic events is desirable. Statistically significant differences in the TAT results between group A and B at the end of puerperium revealed that the recommended extended LMWH prophylaxis until the end of puerperium was not followed by a number of women who started the prophylaxis on the date of labor.