Safety of Pregnancy After Cerebral Venous Thrombosis: A Systematic Review.

BACKGROUND AND PURPOSE: Pregnancy and puerperium are associated with an increased risk of venous thrombotic events (VTEs), including cerebral venous thrombosis (CVT). We aimed to systematically review, in pregnant woman with previous CVT, (1) the risk of recurrence of CVT or other VTE; (2) the result of pregnancy; and (3) the association of antithrombotic prophylaxis with these outcomes.

METHODS: We searched MEDLINE, Cochrane Database of Systematic Reviews, clinicaltrials.gov (from inception to July 2015), and reference lists of included studies and review articles. We considered observational studies reporting original data on the frequency of CVT or other VTE associated with pregnancy or puerperium in women with history of CVT.

RESULTS: Thirteen studies were included. A simple pooled analysis of individual patient data and meta-analysis of proportions using a random effect model were performed. (1) 1 CVT recurrences/217 pregnancies (9 per 1000; 95% confidence interval, 3-33) and 5 noncerebral VTE/186 pregnancies (27 per 1000; 95% confidence interval, 12-61). (2) Pregnancy outcome: 33 spontaneous abortions/186 pregnancies (17.7%; 95% confidence interval, 13-24). (3) Data on the risk of CVT/extracerebral VTE according to antithrombotic prophylaxis was limited. Miscarriage did not differ significantly in women undergoing antithrombotic therapy or not (11.3% versus 18.8%; P=0.34).

CONCLUSIONS: In women with previous CVT, the absolute risk of pregnancy-related venous thrombosis is low but the relative risk of noncerebral VTE is 16-fold higher and the recurrence of CVT is 80-fold higher than the baseline risk described in general population studies. The rate of miscarriage is not significantly different from that estimated for the general population.