Antithrombotic prophylaxis in women with thrombophilia and pregnancy complications

[Late prognosis after preeclampsia]

Preeclampsia, eclampsia and HELLP syndrome are severe complications of pregnancy associated with a high morbidity and mortality for both mother and foetus. The issue of prognosis with regards to risk of relapse is therefore of upmost importance for both the patients and doctors managing their subsequent pregnancies. The overall risk of relapse is estimated to be less than 10%. The risk is especially increased in case of early onset, before the 28(th) week of amenorrhea. In such patients, an underlying renal disease, essential hypertension or secondary hypertension might be identified. A renal consultation must ensure the complete resolution of the hypertension and proteinuria, otherwise investigations need to be carried out looking for an underlying renal or vascular disease affecting the renal parenchyma or outflow. Screening for a hereditary thrombophilia is performed in the immediate post-partum period following and early onset PE, especially if associated with an IUGR, fetal death, or in an early and severe relapse. A renal biopsy is only rarely considered: it is either performed within the first post-partum days whenever a systemic disease flare-up is suspected (i.e. SLE), or late if the proteinuria failed to settle beyond 6 months post-part. Severe PE is a marker of a vascular disease of short duration, but must be considered a risk factor for later atherosclerosis with cardiovascular complications, justifying long term cardiovascular, renal and metabolic follow-up.

Thromboembolism in pregnancy

PURPOSE OF REVIEW

Venous thromboembolism is the leading cause of maternal death in the UK. Thrombophilia underlies many thrombotic disorders in pregnancy. The high prevalence of thrombophilic defects in the population, the association of defects with venous thromboembolism and the special considerations for management make it a widely debated subject.

RECENT FINDINGS

A limited number of studies measuring the risk of venous thromboembolism in pregnancy with thrombophilia have been conducted within the last year. Studies confirm that heritable thrombophilias are associated with increased risk of venous thromboembolism in pregnancy. However, estimated risks vary between individual studies. The risk of venous thromboembolism with acquired thrombophilia remains unclear. Guidelines have been published to guide clinicians in preventing and treating venous thromboembolism in pregnancy; however, large-scale, randomized controlled trials need to be conducted to establish the effectiveness of administering antithrombotic agents in pregnancy. Although selective thrombophilia screening based on prior history of venous thromboembolism has been proposed, the overall clinical and economic benefit of universal and selective screening is unsupported.

SUMMARY

Due to the lack of studies, gaps still exist in our knowledge of the risk of pregnancy-related venous thromboembolism associated with thrombophilia. In particular, accurate estimates are required for the risks of acquired thrombophilias. Furthermore, the true effectiveness of anticolagulants in pregnancy needs to be established through well-conducted studies and randomized controlled trials. These studies will inform clinicians and help to determine the optimum management and prevention strategies for thrombophilia and venous thromboembolism in pregnancy.