Pregnancy outcome after a first episode of cerebral vein thrombosis: comment

Abstract

We read with great interest the article by Martinelli et al. 1.Martinelli I. Passamonti S.M. Maino A. Abbattista M. Bucciarelli P. Somigliana E. Artoni A. Gianniello F. Peyvandi F. Pregnancy outcome after a first episode of cerebral vein thrombosis.J Thromb Haemost. 2016; 14: 2386-93Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar, in which the authors report their attempt to evaluate the risk of obstetric complications, recurrent venous thrombosis and bleeding in a cohort of pregnant women receiving low molecular weight heparin (LMWH) after a first episode of cerebral vein thrombosis (CVT). They also estimated the relative risk of obstetric complications; patients with previous CVT were compared with a cohort of healthy women without thrombosis and with at least one pregnancy in their life. In their observational database of 52 patients and 204 healthy women, the risk of developing late obstetric complications was 24% (95% confidence interval [CI] 18–38%), leading to a relative risk of 6.09 (95% CI 2.46–15.05). As far as we know, this is the first observational study designed to investigate the obstetric outcome of women receiving antithrombotic prophylaxis with LMWH because of a previous episode of CVT, the rate of recurrence of thrombosis, and the safety of prophylaxis during pregnancy. In brief, in patients, the most frequently involved sinuses were the lateral and the superior sagittal, and in 38% of patients CVT occurred in more than one sinus. The most common transient risk factor at the time of CVT was oral contraceptive use (81% versus 17% in healthy women), followed by pregnancy or puerperium (17%). Patients and healthy women had similar risks of miscarriage (2% and 9%, respectively), but differed in their risk of late obstetric complications, which were observed in 24% and 4% of women, respectively, giving a relative risk of 6.09 (95% CI 2.46–15.05). Among patients with thrombophilia, 12 (80%) had a term index pregnancy and three (20%) had obstetric complications, and, when the last 17 pregnancies before CVT were compared with the first 17 pregnancies after CVT, the rates of late obstetric complications were 13% and 40%, respectively, and those of termination were 6% and 41%, respectively. CVT is a rare life‐threatening disease that occurs in three to four adult individuals per one million per year 2.Dentali F. Gianni M. Crowther M.A. Ageno W. Natural history of cerebral vein thrombosis: a systematic review.Nat Hist. 2006; 108: 1129-34Google Scholar. Because of a strong association between CVT and oral contraceptive use or pregnancy/puerperium, women of childbearing age account for two‐thirds of described cases. The risk of recurrent venous thromboembolis is higher than that of recurrent CVT 3.Dentali F. Poli D. Scoditti U. di Minno M.N.D. Stefano V.D. Siragusa S. Kostal M. Palareti G. Sartori M.T. Grandone E. Vedovati M.C. Ageno W. Falanga A. Lerede T. Bianchi M. Testa S. Witt D. McCool K. Bucherini E. Grifoni E. et al.Long‐term outcomes of patients with cerebral vein thrombosis: a multicenter study.J Thromb Haemost. 2012; 10: 1297-302Crossref PubMed Scopus (113) Google Scholar. In pregnancy, LMWH prophylaxis lowers the risk of recurrent thrombosis in women with previous venous thromboembolism, but not that of late obstetric complications 4.Schulman S. Kearon C. Subcommittee on Control of Anticoagulation of the Scientific and Standardization Committee of the International Society on Thrombosis and HaemostasisDefinition of major bleeding in clinical investigations of antihemostatic medicinal products in non‐surgical patients.J Thromb Haemost. 2005; 3: 692-4Crossref PubMed Scopus (3116) Google Scholar. We agree with Martinelli et al. 1.Martinelli I. Passamonti S.M. Maino A. Abbattista M. Bucciarelli P. Somigliana E. Artoni A. Gianniello F. Peyvandi F. Pregnancy outcome after a first episode of cerebral vein thrombosis.J Thromb Haemost. 2016; 14: 2386-93Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar that pregnant women who receive an intermediate dose of LMWH for thromboprophylaxis have a low risk of developing recurrent thrombosis, bleeding episodes, or other heparin‐related side‐effects. We believe that the research by Martinelli et al. 1.Martinelli I. Passamonti S.M. Maino A. Abbattista M. Bucciarelli P. Somigliana E. Artoni A. Gianniello F. Peyvandi F. Pregnancy outcome after a first episode of cerebral vein thrombosis.J Thromb Haemost. 2016; 14: 2386-93Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar will greatly promote further research on treatment of pregnant women with LMWH. However, this study was limited to a single center and small sample sizes of certain patient subgroups, so the results may not be generalizable to all institutions. Therefore, we would encourage the authors to conduct a large prospective randomized controlled trial of LMWH therapy to determine pregnancy outcome. The authors state that they have no conflict of interest.