Management of rare inherited bleeding disorders: Proposals of the French Reference Centre on Haemophilia and Rare Coagulation Disorders.

INTRODUCTION: The rare coagulation disorders may present significant difficulties in diagnosis and management. In addition, considerable inter-individual variation in bleeding phenotype is observed amongst affected individuals, making the bleeding risk difficult to assess in affected individuals. The last international recommendations on rare inherited bleeding disorders (RIBDs) were published by the United Kingdom Haemophilia Centre Doctors' Organisation in 2014. Since then, new drugs have been marketed, news studies on surgery management in patients with RIBD have been published, and new orphan diseases have been described. AIM: Therefore, the two main objectives of this review, based on the recent recommendations published by the French Reference Centre on Haemophilia and Rare Bleeding Disorders, are: (i) to briefly describe RIBD (clinical presentation and diagnostic work-up) to help physicians in patient screening for the early detection of such disorders; and (ii) to focus on the current management of acute haemorrhages and long term prophylaxis, surgical interventions, and pregnancy/delivery in patients with RIBD.

Report of surgeries, their outcome and the thrombin generation assay in patients with Factor XI deficiency: A retrospective single-centre study.

BACKGROUND: In patients with FXI deficiency, the risk of surgery-related bleeding is poorly correlated with plasma FXI activity (FXI:C); the latter can therefore not be used as a reliable predictor of bleeding in surgeries. OBJECTIVES: The aim of this retrospective study was to determine whether thrombin generation assay (TGA) could be used to evaluate the risk of surgery-related bleeding in FXI-deficient patients. TGA parameters were compared to FXI:C values, haemostatic treatments and surgical outcomes. PATIENTS: All patients followed at the haemophilia treatment care centre (Lyon, France) with a FXI:C < 50IU/dL, and for whom a baseline TGA was performed between January 2014 and December 2019, were included. RESULTS: Among the 175 surgeries reported herein in 49 patients, FXI concentrates were used for 11 (6%) surgeries and fresh frozen plasma was used for five (3%) surgeries; these surgeries were performed in patients with two or three impaired TGA parameters. No haemostatic treatment was prescribed for 119 (68%) surgeries. A surgery-related bleeding occurred in 12 patients during 21 (12%) surgeries. Thrombin generation was significantly reduced or delayed in patients who reported surgery related-bleeding. Among the 34 (68%) surgeries performed without haemostatic treatment in patients with three impaired TGA parameters, a surgery-related bleeding was reported in 44% of cases (15 surgeries out of 34). CONCLUSION: The present study confirmed that TGA is an interesting laboratory test in FXI deficiency, for determining the bleeding risk and guiding the haemostatic management of surgeries, while taking into account the surgical bleeding risk and the history of bleeding.

Effectiveness of long-term prophylaxis using pdFVIII/VWF concentrate in patients with inherited von Willebrand disease.

BACKGROUND: Patients with symptomatic von Willebrand disease (VWD) should be offered long-term prophylaxis (LTP) to prevent recurrent bleedings. Our objective was to evaluate the effectiveness and safety of Voncento®, a plasma-derived FVIII/VWF concentrate (ratio 1:2.4), administrated in LTP. METHODS: We included patients from the OPALE study (May 2016 to April 2021), a French multicenter observational study following patients with inherited VWD, who received a Voncento® LTP during the study period. RESULTS: Among the 130 OPALE-study patients, 23 patients (12 women) received a LTP and were therefore included. The median (range) age was 16 (1-85) years; 16 patients were type 3, 1 was type 2A, 6 were type 2B. Before inclusion, 19 (83%) were under LTP and 4 (17%) received on-demand (OD) treatment. The indications for initiating prophylaxis in the overall population were joint bleeding (43%), ear, nose, and throat (ENT) bleeding including epistaxis or oral bleeding (39%), and recurrent muscle hematoma (22%). The medians (ranges) dose of Voncento® per infusion, frequency, and weekly dose were 45 (33-109) IU/kg, 2 infusions per week, and 96 (44-222) IU/kg/week, respectively. The median (range) annualized bleeding rate (ABR) was 0.8, 0.7 (0-3.5), and 0 (0-2.3) for type 2A, 2B, 3 patients, respectively. There was no difference regarding to the dose, frequency of infusion, or in terms of ABR in 9/19 patients who replaced previous concentrates with Voncento®. During the study period, no adverse event was reported. CONCLUSION: These results suggest that Voncento® is effective to prevent recurrent bleedings in patients symptomatic VWD.

Acquired factor V inhibitor: a nation-wide study of 38 patients.

Acquired factor V inhibitor (AFVI) is an extremely rare disorder that may cause severe bleeding. To identify factors associated with bleeding risk in AFVI patients, a national, multicentre, retrospective study was made including all AFVI patients followed in 21 centres in France between 1988 and 2015. All patients had an isolated factor V (FV) deficiency <50% associated with inhibitor activity. Patients with constitutional FV deficiency and other causes of acquired coagulation FV deficiencies were excluded. The primary outcome was incident bleeding and factors associated with the primary outcome were identified. Thirty-eight (74 [36-100] years, 42·1% females) patients with AFVI were analysed. Bleeding was reported in 18 (47·4%) patients at diagnosis and in three (7·9%) during follow-up (7 [0·2-48.7] months). At diagnosis, FV was <10% in 31 (81·6%) patients. Bleeding at diagnosis was associated with a prolonged prothrombin time that strongly correlated with the AFVI level measured in plasma {r = 0·63, 95% confidence interval (CI) [0·36-0·80], P < 0·05}. Bleeding onset during follow-up was associated with a slow AFVI clearance (P < 0·001). The corresponding receiver operating characteristics curve showed that AFVI clearance was predictive of bleeding onset with an AFVI clearance of seven months with a sensitivity of 100% (95% CI: 29-100) and a specificity of 86% (95% CI: 57-98, P = 0·02). Kaplan-Meier analysis showed that AFVI clearance >7 months increased the risk of bleeding by 8 (95% CI: [0·67-97], P = 0·075). Prothrombin time at diagnosis and time for clearance of FV inhibitor during follow-up are both associated with bleeding in patients with AFVI.

Congenital factor XIII deficiency: comprehensive overview of the FranceCoag cohort.

This FranceCoag network study assessed 33 patients with congenital factor XIII (FXIII) deficiency presenting FXIII levels <10 iu/dl. Diagnosis was based on abnormal bleeding in 29 patients, a positive family history in 2, recurrent miscarriages in 1 and was fortuitous in 1. Eighteen patients (62·1%) presented life-threatening umbilical or intracranial haemorrhages (ICH). Seven of the 15 patients who experienced ICH were diagnosed but untreated, including 3 with secondary neurological sequelae. All pregnancies without prophylaxis (26/26) led to miscarriages versus 3/16 with prophylaxis. In patients exhibiting FXIII levels <10 iu/dl, prophylaxis could be discussed at diagnosis and at pregnancy. Further controlled prospective studies are needed.

Differential diagnosis of neonatal alloimmune thrombocytopenia: Type 2B von Willebrand disease.

At birth, severe thrombocytopenia without context of infection should mainly suggest neonatal alloimmune thrombocytopenia (NAIT), especially in case of a platelet count below 20 GL-1. We report two cases of severe neonatal thrombocytopenia, first suspected as being NAIT. Both had a platelet count below 20 GL-1 with platelet clumps. The absence of alloantibodies and failure of platelet transfusion and intravenous immunoglobulins to improve the platelet count led to question the diagnosis and to evoke inherited bleeding disorders. Measurements of Von Willebrand factor (VWF) levels showed a marked reduction of VWF:RCo and a normal VWF:Ag, suggesting a type 2B Von Willebrand disease (VWD2B). Ristocetin-induced platelet aggregation could not be performed because of the very low platelet count. In the first case, after sequencing VWF exon 28, a heterozygous p.Leu1460Pro mutation was found consistent with VWD2B. In the second case, the genetic analysis of VWF exon 28 identified a homozygous mutation: p.Pro1337Leu confirming type VWD2B and also the p.Arg854Gln homozygous mutation in exon 20 confirming type 2N (ratio FVIII/VWF:Ag <0.5). The two cases underline that, even if NAIT remains the most common diagnosis in severe neonatal thrombocytopenia, it should be challenged in the absence of documented incompatibility, chronic evolution, or treatment failure. Diagnosis of VWD2B should be considered in early thrombocytopenia, even without familial history. In the cases presented, genotyping confirmed the subtype of VWD and helped to guide the therapeutic management of bleeding episodes.

A Systematic Review of Efficacy and Safety of Plasma-Derived von Willebrand Factor/Factor VIII Concentrate (Voncento) in von Willebrand Disease.

BACKGROUND: For the treatment of von Willebrand disease (VWD), von Willebrand factor (VWF) concentrates can be used in on-demand, long-term prophylaxis, and surgical prophylaxis regimens. METHODS: This systematic literature review was conducted to evaluate the efficacy, consumption, and safety of plasma-derived human coagulation FVIII/human VWF (pdVWF/FVIII; Voncento/Biostate) for the treatment of patients with any inherited VWD type. An electronic search was conducted in MEDLINE and Cochrane Library databases on VWD therapies. All retrieved publications were assessed against predefined inclusion/exclusion criteria following the Cochrane group recommendations. Associated pharmacovigilance data were collected across the same time period. RESULTS: Eleven publications from eight study cohorts were identified for data retrieval. All were from multicenter studies and included both pediatric and adult patients. Eight publications included evaluations of the efficacy of pdVWF/FVIII for on-demand treatment, eight included long-term prophylactic treatment, and eight included surgical prophylaxis. Treatment protocols and VWF administration methods differed between studies, as did safety evaluations. The clinical response was rated as excellent/good for on-demand treatment in 66 to 100% of nonsurgical bleeds, 89 to 100% in the treatment of breakthrough bleeds during long-term prophylaxis treatment, and hemostatic efficacy in surgical procedures was 75 to 100%. Pharmacovigilance data confirmed a low incidence of adverse events in treated patients. CONCLUSION: This review provides a comprehensive summary of studies that evaluated the use of pdVWF/FVIII in VWD demonstrating the long-term effectiveness and safety of this pdVWF/FVIII across all ages, types of VWD, and treatment settings.

Progressive endothelial damage revealed by multilevel von Willebrand factor plasma concentrations in atrial fibrillation patients.

AIMS: Abnormal plasma concentrations of von Willebrand factor (vWF), a marker of prothrombotic risk, have been found in atrial fibrillation (AF) patients, but the extent of this variation is not clear. This study aimed to investigate the effect of different clinical forms of AF on plasma concentrations of vWF at different levels of the circulatory tree, both intracardiac and extracardiac. METHODS AND RESULTS: Peripheral (Pf), left atrial (LA), and coronary sinus (CS) blood samples were obtained during cardiac catheterization from 52 patients with paroxysmal AF (PAF), 36 with persistent AF (PsAF), and 17 control subjects (Ct) with left-sided accessory pathway Wolff-Parkinson-White syndrome. Plasma concentrations of vWF were determined by immunoturbidimetry. Compared with Ct, patients with PAF had higher LA plasma levels of vWF (P = 0.004), but similar Pf and CS levels (both P > 0.30). In contrast, patients with PsAF had higher plasma concentrations of vWF in Pf (P = 0.04), LA (P < 0.001), and CS (P = 0.04) samples compared with Ct. Left atrial plasma concentrations of vWF in patients with PsAF were also higher than in the PAF group (P = 0.04). CONCLUSION: Regardless of the clinical form of the arrhythmia, AF patients presented significantly higher plasma concentrations of vWF compared with sinus rhythm controls. Multilevel vWF plasma concentration assessment suggests an association between the clinical evolution of AF and the progression of endothelial dysfunction. Further studies will have to establish the exact mechanisms that link endothelial dysfunction and stroke in the context of AF.

Multicolor flow cytometry in clinical samples for platelet signaling assessment.

Background: Availability of multichannel cytometers and specific commercial antibodies makes flow cytometry a new option to simultaneously assess multiple intracellular platelet signaling pathways for clinical purposes, in small volume of blood or low platelet count. Objectives: To describe a multicolor flow cytometry with fluorescent barcoding technique for screening signaling pathways downstream membrane receptors of major platelet agonists (adenosine diphosphate, thrombin, thromboxane, and collagen). Methods: By comparison with immunoblotting, we first selected the target phosphoproteins, AKT, P38MAPK, LIMK, and SPL76; the times of stimulation; and phosphoflow barcoding conditions. We then performed a clinical study on whole blood of patients without evidence of blood platelet disorder on standard biological screening, consulting for trivial or occasionally provoked bleeds without familial antecedent (bleeding of unknown origin, n = 23) or type-1 von Willebrand disease (n = 9). In addition, we included a small group of patients with definite platelet disorders (Glanzmann thrombasthenia, δ-storage pool deficiency, and immune glycoprotein VI-related disease with granule secretion defect). Results: The range, kinetics, and distribution of fluorescence intensity were established for each agonist-target protein combination. Principal component analysis indicates a correlation in response to a target phosphoprotein (AKT and P38MAPK) to different agonists but no correlation in the response of different target phosphoproteins to the same agonist. The heterogeneity of individual responses in the whole population displayed was analyzed using clustering algorithm. Patients with platelet storage pool deficiency were positioned as lowest responders on the heatmap. Conclusion: In complement of functional tests, this study introduces a new approach for rapid platelet signaling profiling in clinical practice.

Surgery in rare bleeding disorders: the prospective MARACHI study.

Background: Despite the wide use of bleeding scores and the reliability of clotting factor level measurement, bleeding risk stratification before surgery remains challenging in patients with rare inherited bleeding disorders. Objectives: This multicenter observational prospective study assessed in patients with rare coagulation factor deficiency, the perioperative hemostatic management choices by hemostasis experts and the bleeding outcomes after surgery. Methods: One hundred seventy-eight patients with low coagulation activity level (factor [F] II, FV, combined FV-FVIII, FVII, FX, or FXI <50%) underwent 207 surgical procedures. The bleeding outcome, Tosetto's bleeding score, and perioperative hemostatic protocols were collected. Results: Among the 81 procedures performed in patients with severe factor deficiency (level ≤10%), 27 were done without factor replacement (including 6 in patients at high bleeding risk), without any bleeding event. Factor replacement therapy was used mainly for orthopedic procedures. In patients with mild deficiency, 100/126 surgical procedures were carried out without perioperative hemostatic treatment. In patients with FVII or FXI deficiency, factor replacement therapy was in function of the procedure, bleeding risk, and to a lesser extent previous bleeding history. Tranexamic acid was used in almost half of the procedures, particularly in case of surgery in tissues with high fibrinolytic activity (76.8%). Conclusions: The current perioperative hemostatic management of patients with rare bleeding disorders appears to be adapted. Among the 207 procedures, only 6 were associated with excessive bleeding. Our findings suggest that rather than the bleeding score, factor level and surgery type are the most relevant criteria for perioperative factor replacement therapy.

Continuous Infusion of Factor VIII and von Willebrand Factor in Surgery: Trials with pdFVIII LFB or pdVWF LFB in Patients with Bleeding Disorders.

BACKGROUND: A plasma-derived factor VIII product (pdFVIII; Factane 100 or 200 IU/mL) and a plasma-derived von Willebrand factor product (pdVWF; Wilfactin 100 IU/mL) are approved for replacement therapy by intravenous bolus injections in hemophilia A (HA) and von Willebrand disease (VWD), respectively. However, in situations requiring intensive treatment, continuous infusion (CI) may be desirable to better control target plasma factor levels. AIM: To evaluate the perioperative hemostatic efficacy and safety of these concentrates administered by CI. METHODS: Three phase III trials were conducted. Adults with HA (FVIII:C < 1%) (studies 1 and 2) or VWD (VWF:RCo < 20%) (Study 3) received a preoperative bolus followed by CI of undiluted concentrate for at least 6 days. Bolus doses and CI rates were based on individual recovery and clearance, respectively. The initial infusion rate had to be higher for 48 hours for HA and 24 hours for VWD patients to anticipate potential fluctuations of factor concentrations during major surgery. Target levels of FVIII:C in HA and VWF:RCo in VWD were 80 and 70 IU/dL, respectively. Efficacy was assessed using a global hemostatic efficacy score. RESULTS: Studies 1, 2, and 3 included 12, 4, and 6 patients, respectively. Efficacy outcomes were excellent/good in all 22 major surgeries including 18 orthopedic procedures. Most daily measured FVIII and VWF levels (92%) were on target. No safety concerns, thrombotic events, or inhibitors were identified. CONCLUSION: pdFVIII and pdVWF administered by CI represent an effective and safe alternative to bolus injections in patients with severe HA or VWD undergoing surgery.

Effectiveness and safety of hFVIII/VWF concentrate (Voncento®) in patients with inherited von Willebrand disease requiring surgical procedures: the OPALE multicentre observational study.

BACKGROUND: In patients with moderate to severe qualitative and quantitative von Willebrand disease (VWD), even minor surgical procedures can be associated with a risk of life-threatening bleeding. Treatment strategies vary according to the levels of von Willebrand factor (VWF) and Factor VIII (FVIII). The aim of this study was to evaluate the effectiveness and the safety of Voncento® (CSL Behring, Marburg, Germany), a plasma-derived FVIII/VWF concentrate (ratio 1:2.4), during surgeries performed in patients with inherited VWD. MATERIALS AND METHODS: The OPALE study, a French multicentre observational study, was carried out from May 2016 to May 2019. It evaluated and analysed patients with inherited VWD (any type) requiring treatment with Voncento® who underwent surgery. RESULTS: In total, 92 patients were enrolled, and 66 patients underwent 100 surgical procedures: 69 minor and 31 major surgeries conducted in 30 patients with type 1, 50 patients with type 2, and 20 patients with type 3 VWD. During minor surgeries, the median number of infusions was one (range: 1-9), the pre-operative loading dose was 41 IU VWF:RCo kg-1 (range: 18-147), and the total dose was 63 (range: 18-594). During major surgeries, the number of infusions was 4 (range: 1-23), the pre-operative loading dose was 43 (range: 25-66) IU VWF: RCo kg-1, and the total dose was 155 (range: 40-575). The median FVIII:C levels ranged from 78 to 165 IU dL-1 during 5 days after minor surgeries and from 86 and 167 IU dL-1 during 11 days after major surgeries. VW:RCo levels ranged between 35 and 65 IU dL-1 and between 34 and 76 IU dL-1 after minor and major surgeries, respectively. The overall clinical effectiveness was qualified as "excellent" or "good" in 99% of patients. No thrombotic events related to Voncento® were recorded. DISCUSSION: The present study suggests that Voncento® is an effective and well-tolerated therapy for the peri-operative management of patients with all VWD types.

[Assessment of the interest of using confirmatory test in ELISA with use of high concentration of heparin-induced thrombocytopenia]. / Évaluation de l'intérêt du test de confirmation avec une forte concentration d'héparine en Elisa dans la thrombopénie induite par l'héparine.

Heparin-induced thrombocytopenia (HIT) is a severe complication of heparin therapy caused by an antibody against heparin/Platelet Factor 4 (PF4) complex. It complicates the treatment with unfractionated heparin (UFH). The aim of the study was to assess the interest of using confirmatory test in ELISA with use of high concentration of heparin (100 UI/mL) in patients (n=15) with discordance between platelet activation test and ELISA test. We obtained a rate inhibition higher than 50% in 86% of patients was observed. We conclude that inclusion of the high heparin confirmatory procedure in ELISA demonstrate the dependent heparin character of the antibodies but does not improve diagnostic specificity. In addiction a 2-fold increase in final test cost is observed.

Pregnancy-related thrombosis risk in patients with protein C deficiency and comparison with pregnant women with heterozygous factor V Leiden mutation.

: The risk of pregnancy-related venous thromboembolism is high in patients with inherited thrombophilia. The aim of this study was to compare the risk of pregnancy related-venous thromboembolism of women with protein C (PC) deficiency to patients with heterozygous factor V Leiden mutation. 145 consecutive pregnant women with confirmed PC deficiency or heterozygous factor V Leiden mutation were prospectively enrolled in the study. Lyon venous thromboembolism-risk score was used to individually tailor antithrombotic prophylaxis. The use of a validated clinical score presents the advantage to have a homogenous management of the venous thromboembolism risk in patients having similar risk factors. 53 pregnancies with PC deficiency were compared with 190 pregnancies in heterozygous factor V Leiden mutation carriers. 50% of the patients with PC deficiency and 64% of the heterozygous factor V Leiden mutation carriers were asymptomatic. According to the Lyon-venous thromboembolism risk score, 50% of patients with PC deficiency and 51% of heterozygous factor V Leiden carriers did not received any antepartum heparin prophylaxis. 34 and 37% of patients respectively received heparin prophylaxis during the third trimester only. No venous thromboembolism was observed in patients with PC deficiency and one postpartum venous thromboembolism occurred in a patient with heterozygous factor V Leiden. In the absence of randomized controlled clinical studies, we report here a large prospective series of pregnant women with PC deficiency. In our cohort, no difference of outcome, in terms of venous thromboembolism, was observed between pregnant women with PC deficiency and those with heterozygous factor V Leiden. Based on our results, low-molecular-weight heparin prophylaxis should not be mandatory in all pregnant women with PC deficiency. Similar prophylaxis strategies may be applied to women with factor V Leiden mutation or PC deficiency.

Gynecological and obstetric outcome in the French cohort of women with factor XIII deficiency.

INTRODUCTION: Congenital factor XIII deficiency is a very rare bleeding disorder affecting 33 patients in France. Besides its role in fibrin clot stabilization, factor XIII is involved in placental attachment. Fetal miscarriages represent a frequent and concerning issue for these patients. The aim of the present study was to describe clinical characteristics of women presenting severe congenital FXIII deficiency in France, to focus on gynecological and obstetrical events, and to report the management of these rare situations. METHODS: We conducted a retrospective study in the French Hemophilia Comprehensive Care and Clinical Hemostasis Centers. Women between 15 and 65 years with factor XIII activity <10 IU dL-1 were included. Biological, clinical and therapeutic events that occurred to these patients during their gynecological and obstetrical period were recorded. RESULTS: Among 31 centers, eleven patients were included. The median age at diagnosis was 1.5 years (range: 0-35), and at inclusion it was 30 years (range: 15-63). Fetal miscarriage was the primary manifestations in 2 (18%) patients, the remaining were diagnosed during hemorrhage. Menorrhagias were reported by 2 women (27%), 13 pregnancies were reported by 9 women including one abortion. Every pregnancy was conducted under factor XIII substitution, no hemorrhagic episode was reported. Four patients (36%) experienced at least one fetal miscarriage with a total amount of 30 miscarriages with 6 occurring during substitution. CONCLUSION: Altogether, our data confirmed the high incidence of miscarriage in women with factor XIII deficiency. Good outcome of pregnancies required prophylaxis in accordance with international guidelines.

Comparative Analysis of a French Prospective Series of 144 Patients with Heparin-Induced Thrombocytopenia (FRIGTIH) and the Literature.

BACKGROUND: Heparin-induced thrombocytopenia (HIT) is a rare complication of heparin treatments, and only a few large patient cohorts have been reported. In this study, biological and clinical data from 144 French patients with HIT were analyzed in comparison with the literature. METHODS: The diagnosis of HIT was confirmed in all patients by an immunoassay combined with serotonin release assay. In the literature, only cohorts of at least 20 HIT patients published from 1992 were selected for a comparative analysis. RESULTS: Two-thirds of patients were hospitalized in surgery and most were treated with unfractionated heparin (83.2% vs. 16.8% with low molecular weight heparin only). Thrombotic events in 54 patients (39.7%) were mainly venous (41/54). However, arterial thrombosis was more frequent after cardiac surgery (13.2% vs. 2.4% in other surgeries, p = 0.042) with a shorter recovery time (median = 3 vs. 5 days, p < 0.001). The mortality rate was lower in our series than in the 22 selected published studies (median = 6.3% vs. 15.9%). Three genetic polymorphisms were also studied and homozygous subjects FcγRIIA RR were more frequent in patients with thrombosis (37.8 vs. 18.2% in those without thrombosis, p = 0.03). CONCLUSION: This study shows that the mortality rate due to HIT has recently decreased in France, possibly due to earlier diagnosis and improved medical care. It also confirms the strong association between polymorphism FcγRIIA H131R and thrombosis in HIT.

A risk score for the management of pregnant women with increased risk of venous thromboembolism: a multicentre prospective study.

Patients with thrombophilia and/or a history of venous thromboembolism (VTE) exhibit a high risk of thrombosis during pregnancy. The present multicentre study prospectively assessed a prophylaxis strategy, based on a risk score, in pregnancies with increased risk of VTE. Among 286 patients included in the study, 183 had a personal history of VTE (63.98%) and 191 patients (66.8%) had a thrombophilia marker. Eighty nine (46.6%) thrombophilic women had a personal history of VTE. Patients were assigned to one of three prophylaxis strategies according to the risk scoring system. In postpartum, all patients received low molecular weight heparin (LMWH) prophylaxis for at least 6 weeks. In antepartum, LMWH prophylaxis was prescribed to 61.8% of patients with high risk of VTE. Among them, 37.7% were treated in the third trimester only and 24.1% were treated throughout pregnancy. In this cohort, one antepartum-related VTE (0.35%) and two postpartum-related VTE (0.7%) occurred. No case of pulmonary embolism was observed during the study period. The rate of serious bleeding was 0.35%. There was no evidence of heparin-induced thrombocytopenia or osteoporosis. The use of a risk score may provide a rational decision process to implement safe and effective antepartum thromboprophylaxis in pregnant women at high risk of VTE.