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We used a prospective cohort of pregnant women at 12 to 20 weeks gestation between 2002 and 2008 in Ottawa and Kingston to evaluate the impact of early pregnancy folic acid supplementation on the risk of gestational diabetes mellitus. Among 7552 eligible women, 84 (1.11%) were diagnosed of gestational diabetes mellitus. Non-significant associations were observed between gestational diabetes mellitus and folate supplementation, homocysteine levels, and methylenetetrahydrofolate reductase 677 TT genotype. Although we found no significant associations between folic acid supplementation and the risk of gestational diabetes mellitus, genetic associations were not confounded by lifestyle or socioeconomic factors, which may have biased previous studies.

IntroductionDeciding whether to stop or extend anticoagulant therapy indefinitely after completing at least 3 months of initial treatment for a first unprovoked venous thromboembolism (VTE) remains a challenge for clinicians, patients and policy makers. Guidelines suggest an indefinite duration of anticoagulant therapy in these patients, yet its benefits, harms and costs have not been formally assessed. The aim of this proposed modelling study is to assess the differences in clinical benefits, harms and costs of stopping versus continuing anticoagulant therapy indefinitely for a first unprovoked VTE.Methods and analysisWe will develop a probabilistic Markov model, adopting a 1-month cycle length and a lifetime horizon, to estimate life-years, quality-adjusted life-years, costs and the incremental cost-effectiveness ratios for a simulated population of patients with a first unprovoked VTE who will receive indefinite duration of anticoagulant therapy versus a population who will not receive extended treatment after completing 3 months of initial anticoagulant therapy. The economic evaluation will adopt a third-party payer perspective relating to a Canadian publicly funded healthcare system. Estimates for the probability of relevant clinical events will be informed by systematic reviews and meta-analyses, while costs and utility values will be obtained from published Canadian sources. Stratified analyses based on sex, age and site of initial VTE will also be performed to identify subgroups of patients with a first unprovoked VTE in whom continuing anticoagulant therapy indefinitely might prove to be clinically beneficial and cost-effective over stopping treatment. We will also conduct sensitivity and scenario analyses to assess robustness of study findings to changes in individual or groups of key parameters.Ethics and disseminationEthical approval is not applicable for this study. The results will be disseminated through presentations at relevant conferences and in a manuscript that will be submitted to a peer-reviewed journal.

Education is considered one of the most robust determinants of health. However, it is unclear whether maternal education and paternal education have differential impacts on perinatal health outcomes. We assess maternal and paternal education differences and their association with adverse birth outcomes in a large birth cohort from Ontario, Canada. The OaK Birth Cohort recruited patients from Ontario, Canada, between October 2002 and April 2009. We recruited mothers were recruited between 12 and 20 weeks’ gestation and collected both mother and infant data. The final sample size of the cohort was 8,085 participants. We use logistic regression to model the probability of preterm birth (less than 34 and 37 weeks’ gestation), small-for-gestational-age (SGA), or stillbirth as a function of maternal and paternal educational attainment. We adjust for household-level income, maternal and paternal race and ethnicity, and compare the strength of the association between maternal and paternal education on outcomes using Wald tests. 7,928 mother-father-offspring triads were available for the current analysis. 75% of mothers and fathers had college or university level education, and 8.7% of mothers experienced preterm delivery. Compared to mothers with college or university education, mothers with a high school education had an odds ratio of 1.37 (95% CI: 1.01–1.87) for SGA. Paternal education was not associated with infant outcomes. Comparing the odds ratios for maternal education and paternal education showed a stronger association than paternal education at the high school level for SGA birth (difference in odds ratio: 1.95, 95% CI: 1.13–3.36, p = .016) among women at least 25 years old. Maternal education was associated with SGA, and this effect was more robust than paternal education, but both associations were weaker than previously reported.

The 27th Congress of the International Society of Thrombosis and Haemostasis (ISTH) is an international conference held July 6-10, 2019, in Melbourne, the capital of the state of Victoria, Australia. The ISTH congress has previously been held every other year, with the Scientific and Standardization Committee (SSC) meeting held annually, until 2019 when it became one combined annual meeting of the ISTH and SSC. The conference covers clinical and basic aspects of hemostasis and thrombosis, and this year includes 5 Plenary lectures and >50 State of Art (SOA) lectures, presented by internationally recognized speakers, as well as numerous oral session and poster presentations selected from submitted abstracts, including many early career and reach the world support recipients. This SOA review article in RPTH contains concise Illustrated Review Articles or 'Capsules' consisting of short text, three references and a figure, with topics including stroke, cancer-associated thrombosis, hemophilia, coagulation, the interface between infection and inflammation, and in the experimental and discovery areas, megakaryocyte biology and platelet production, structure-function of key receptors and coagulation factors, and emerging new roles for thrombotic/hemostatic factors. Together, these articles highlight novel findings which will advance knowledge and with the potential to change clinical practice and improve outcomes. It is hoped that conference attendees and followers will enjoy utilizing the images for ongoing education and during the conference for live tweeting during sessions, to assist in the broadcasting and promotion of the science to those unable to attend, or who have chosen to attend a concurrent session. Use #IllustratedReview and #ISTH2019 on social media. ispartof: RESEARCH AND PRACTICE IN THROMBOSIS AND HAEMOSTASIS vol:3 issue:3 pages:431-497 ispartof: location:United States status: published

Acute non-cirrhotic and non-malignant portal vein thrombosis (aPVT) is a rare and heterogenous condition. Current guidelines recommend early initiation of therapeutic anticoagulation to prevent extension of thrombosis, and favor recanalization. Although not formally defined, a poor outcome in the acute setting would include thrombosis extension with progression to intestinal infarction. Patients are also at risk of negative long-term outcomes related to complications of portal hypertension, such as variceal bleeding, ascites, and portal cholangiopathy. Identifying patients at risk of these events despite early initiation of anticoagulation remains challenging. Trials comparing treatment strategies in those failing standard therapy with meaningful radiological and clinical endpoints, whether in the short or long term, are desperately needed. The objective of this review will be to discuss a real-life clinical case and propose a treatment approach for aPVT based on the available evidence. We will mainly focus on management strategies including anticoagulation, prognostic factors, and options beyond anticoagulation, such as thrombolysis, thrombectomy, and transjugular intrahepatic portosystemic shunts. This review will not cover tumor portal vein thrombosis or thrombosis associated with cirrhosis.

Pulmonary embolism (PE) is caused by emboli, which have originated from venous thrombi, travelling to and occluding the arteries of the lung. PE is the most dangerous form of venous thromboembolism, and undiagnosed or untreated PE can be fatal. Acute PE is associated with right ventricular dysfunction, which can lead to arrhythmia, haemodynamic collapse and shock. Furthermore, individuals who survive PE can develop post-PE syndrome, which is characterized by chronic thrombotic remains in the pulmonary arteries, persistent right ventricular dysfunction, decreased quality of life and/or chronic functional limitations. Several important improvements have been made in the diagnostic and therapeutic management of acute PE in recent years, such as the introduction of a simplified diagnostic algorithm for suspected PE as well as phase III trials demonstrating the value of direct oral anticoagulants in acute and extended treatment of venous thromboembolism. Future research should aim to address novel treatment options (for example, fibrinolysis enhancers) and improved methods for predicting long-term complications and defining optimal anticoagulant therapy parameters in individual patients, and to gain a greater understanding of post-PE syndrome.

International audience; Recombinant human antithrombin (rhAT; ATryn), isolated from the milk of transgenic goats, provides an alternative to human plasma-derived antithrombin (AT) concentrate for perioperative and peripartum prophylaxis of venous thromboembolism (VTE) in patients with hereditary AT deficiency. Optimized rhAT dosing algorithms and improved plasma AT monitoring protocol were used in an open-label, single-arm, multinational, pivotal safety and efficacy study that was conducted in patients with hereditary AT deficiency in perioperative and peripartum settings. Loading and maintenance doses were calculated on the basis of pretreatment AT activity levels. Specific dosing regimens were used for pregnant and surgical patients; rhAT was to be given for at least 3 days and for 14 days or less. The primary efficacy end point was the incidence of any thromboembolic event during rhAT therapy or within 7 days of rhAT discontinuation. Safety and AT activity levels were secondary end points. Six surgical and 12 pregnant patients were treated for a median of 3.2 days (range 0.9-14 days). With the optimized dosing regimens, a median of 1 dose adjustment (range 0-6 dose adjustments) was needed to maintain AT activity levels within 80-120% of normal. No confirmed VTEs occurred during treatment or in the subsequent 7 days. Overall, rhAT was well tolerated, but some bleeding complications occurred after rhAT discontinuation and anticoagulation reinstitution. No antibodies to rhAT or goat milk proteins were detected. Perioperative and peripartum prophylactic rhAT therapy in patients with hereditary AT deficiency is well tolerated and effective in preventing VTE.

Objective To present an approach, based on current evidence, for the diagnosis, treatment, and thromboprophylaxis of venous thromboembolism in pregnancy and postpartum. Evidence Published literature was retrieved through searches of PubMed, Medline, CINAHL, and The Cochrane Library from November 2011 to July 2013 using appropriate controlled vocabulary (e.g. pregnancy, venous thromboembolism, deep vein thrombosis, pulmonary embolism, pulmonary thrombosis) and key words (e.g., maternal morbidity, pregnancy complications, thromboprophylaxis, antithrombotic therapy). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies published in English or French. There were no date restrictions. Grey (unpublished) literature was identified through searching the websites of clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. Values The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventative Health Care (Table 1).

Resume Objectif Presenter une approche, fondee sur les donnees actuelles, envers le diagnostic, la prise en charge et la thromboprophylaxie de la thromboembolie veineuse pendant la grossesse et la periode postpartum. Resultats La litterature publiee a ete recuperee par l'intermediaire de recherches menees dans PubMed, Medline, CINAHL et The Cochrane Library entre novembre 2011 et juillet 2013 au moyen d'un vocabulaire controle (p. ex. « pregnancy », « venous thromboembolism », « deep vein thrombosis », « pulmonary embolism », « pulmonary thrombosis ») et de mots cles (p. ex. « maternal morbidity », « pregnancy complications », « thromboprophylaxis », « antithrombotic therapy ») appropries. Les resultats ont ete restreints aux analyses systematiques, aux essais comparatifs randomises / essais cliniques comparatifs et aux etudes observationnelles publies en anglais ou en francais. Aucune restriction n'a ete imposee en matiere de dates. La litterature grise (non publiee) a ete identifiee par l'intermediaire de recherches menees dans les sites Web d'organismes s'interessant a l'evaluation des technologies dans le domaine de la sante et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et aupres de societes de specialite medicale nationales et internationales. Valeurs La qualite des resultats est evaluee au moyen des criteres decrits dans le rapport du Groupe d'etude canadien sur les soins de sante preventifs (Tableau).

Antifibrinolytic agents are commonly used during cardiac surgery to minimize bleeding and to reduce exposure to blood products. We sought to determine whether aprotinin was superior to either tranexamic acid or aminocaproic acid in decreasing massive postoperative bleeding and other clinically important consequences.In this multicenter, blinded trial, we randomly assigned 2331 high-risk cardiac surgical patients to one of three groups: 781 received aprotinin, 770 received tranexamic acid, and 780 received aminocaproic acid. The primary outcome was massive postoperative bleeding. Secondary outcomes included death from any cause at 30 days.The trial was terminated early because of a higher rate of death in patients receiving aprotinin. A total of 74 patients (9.5%) in the aprotinin group had massive bleeding, as compared with 93 (12.1%) in the tranexamic acid group and 94 (12.1%) in the aminocaproic acid group (relative risk in the aprotinin group for both comparisons, 0.79; 95% confidence interval [CI], 0.59 to 1.05). At 30 days, the rate of death from any cause was 6.0% in the aprotinin group, as compared with 3.9% in the tranexamic acid group (relative risk, 1.55; 95% CI, 0.99 to 2.42) and 4.0% in the aminocaproic acid group (relative risk, 1.52; 95% CI, 0.98 to 2.36). The relative risk of death in the aprotinin group, as compared with that in both groups receiving lysine analogues, was 1.53 (95% CI, 1.06 to 2.22).Despite the possibility of a modest reduction in the risk of massive bleeding, the strong and consistent negative mortality trend associated with aprotinin, as compared with the lysine analogues, precludes its use in high-risk cardiac surgery. (Current Controlled Trials number, ISRCTN15166455 [controlled-trials.com].).

Introduction: There is an increased risk of venous thromboembolism (VTE) in patients with essential thrombocythemia (ET), however, what the absolute VTE risk is during pregnancy is largely unknown and is based on small cohort or registry studies. Recommendation for the use of low-molecular-weight heparin (LMWH) prophylaxis in the antepartum and/or postpartum setting is based on the absolute VTE and bleeding risk in other patient populations, for example, in women with inherited thrombophilia. A better estimate of absolute VTE risk will provide guidance for the use of LMWH in pregnant women with ET, as well as other treatments such as interferon. Objective: The aim of our meta-analysis is to quantify the absolute risk of VTE with or without LMWH prophylaxis in women with ET during pregnancy and in the postpartum setting. Methods: A systematic literature search was conducted on MEDLINE, EMBASE and EBM reviews. The primary outcome was VTE and the secondary outcomes were bleeding events and arterial thromboembolism (ATE). Studies were excluded if less than 5 pregnancies were reported, or if there was any duplication in publication, then only the most recent study was included. Using a standardized form, data was extracted independently by two investigators with disagreements resolved by consensus (L.S. and M.A.R.). Data on the use of LMWH, aspirin (ASA) and interferon was collected. Primary and secondary outcomes were reported per pregnancy in the antepartum and postpartum setting using pooled proportions, with 95% confidence intervals reported. Pregnancies ending in first trimester loss were excluded from the postpartum VTE analysis. Peripartum bleeding (delivery to 24 hours) was excluded. Placental abruptions were included as bleeding events. Results: There were 21 studies included that reported outcomes of interest in 504 patients and 756 pregnancies (1991-2016). Ten authors provided additional data. Among 756 pregnancies, there were 8 VTE events in the antepartum setting (1.06%, 95% CI, 0.54-2.07). Among 607 pregnancies (excluding first trimester losses), there were 8 VTE events in the postpartum setting (1.32%, 95% CI, 0.67-2.58). Of the 18 studies that reported VTE with respect to antepartum LMWH prophylaxis use, there were 0 antepartum VTE events among 82 pregnancies with LMWH use (0%, 95% CI, 0.0-4.48), and 8 antepartum VTE events among 407 pregnancies without LMWH use (1.97%, 95% CI, 1.00-3.83). Of the 14 studies that reported VTE with respect to postpartum LMWH prophylaxis use in pregnancies that excluded first trimester losses, there were 0 postpartum VTE events among 96 pregnancies with LMWH use (0%, 95% CI, 0.0-3.85), and 6 postpartum VTE events among 229 pregnancies without LMWH use (2.62%, 95% CI, 1.21-5.60) (Table 1). There were 12 antepartum bleeds reported in 756 pregnancies (1.59%, 95% CI, 0.91-2.75), 9 of which were placental abruptions (1.19%, 95% CI, 0.63-2.25). There were 11 postpartum bleeds reported in 756 pregnancies (1.46%, 95% CI 0.81-2.59). Bleeding according to LMWH prophylaxis use in the antepartum and postpartum setting is presented in Table 1. Among 756 pregnancies, there were 4 possible ATE events described in the antepartum setting: transient visual loss after ASA was held for 1 week, an ocular TIA at 6 weeks gestation while on ASA, and 2 patients who described both visual disturbance and dizziness with unknown ASA use. No patient with possible ATE received LMWH prophylaxis. Conclusion: Women with ET who are pregnant have an increased risk of VTE in both the antepartum and postpartum setting compared to the general pregnant population. The absolute risk of VTE in the antepartum and postpartum setting is not above a threshold where LMWH is clearly indicated or below a threshold where LMWH should be withheld. The role of thromboprophylaxis in this setting requires a shared decision-making process, taking into account patient values and preferences and the risks and benefits of LMWH. Disclosures Carrier: BMS: Research Funding; Leo Pharma: Research Funding. Robinson:Novartis: Honoraria; Pharmacosmos: Honoraria; Amgen: Honoraria. Rodger:Boehringer Ingelheim: Research Funding; Canadian Agency for Drugs and Technologies in Health: Consultancy.

Low-molecular-weight heparin (LMWH) is increasingly being used for prophylaxis of venous thromboembolism (VTE) and prevention of pregnancy associated morbidity in pregnant women with thrombophilia. We sought to determine if the administration of prophylactic doses of LMWH downregulates coagulation activation in high risk pregnant women with thrombophilia. This sub-study was planned as part of a randomized open label controlled trial (Thrombophilia in Pregnancy Prophylaxis Study [TIPPS]) in which patients at high risk of pregnancy complications with confirmed thrombophilia are randomized to receive either dalteparin (5,000 units/day until 20 weeks then 5,000 units q12h until 37 weeks or onset of labor) or no treatment. Blood samples were collected at baseline, day 7-9 (after starting study drug), week 20 (before increasing study drug), week 36 (prior to stopping study drug) and at the time of admission to the labor and delivery unit. Samples were not drawn at fixed times in relation to drug injection. These samples were analyzed for levels of thrombin-antithrombin complexes (TAT), prothrombin fragments 1 + 2 (F1.2), D-dimer and anti-Xa activity. Generalized linear mixed models were used for statistical analysis and model results were controlled for age, smoking status, type of thrombophilia and predisposing risk factors. The effect of dalteparin on TAT levels was defined as the primary outcome. Of 198 patients eligible, 114 were enrolled in TIPPS. Ninety-one were eligible for the TIPPS coagulation activation sub-study and randomized. Thirty-nine patients were analyzed in the treatment group (dalteparin) and 46 patients in the control group (no intervention). Levels of coagulation activation factors F1.2, TAT and D-dimer increased significantly throughout pregnancy in both groups (p0.0001). Dalteparin prophylaxis resulted in a significant increase in anti-Xa activity through pregnancy (p0.0001) compared to controls. Dalteparin had no significant effects on the levels of TAT, F1.2 and D-dimer throughout pregnancy in thrombophilic women. A post-hoc Monte Carlo power analysis revealed that our study had 100% and 88% power to detect reductions in TAT values on treatment of 50% and 25%, respectively. Prophylaxis with dalteparin at doses used in this study did not reduce coagulation activation in high risk thrombophilic women during pregnancy.

Abstract 4209 Background: The risk of recurrent venous thromboembolism (VTE) in patients with cancer-associated VTE, remains high even with the use of low molecular weight heparin (LMWH). However, due to the heterogeneity of the disease it is probable that recurrence risk varies widely. We have developed a prediction rule to classify risk of recurrence in the first 6 months of treatment: + 1 is scored for each of female gender, lung cancer and prior VTE and – 1 is scored for breast cancer and – 2 for TNM stage 1 disease. With a score of ≤ 0, 4.5% of patients recur (this represented 48% of the patient populations), and > 0, 19.7% recur. The rule was derived in a retrospective cohort study of patients followed at the Thrombosis unit of the Ottawa hospital and requires validation. Methods: We applied our rule in a new set of 819 consecutive patients with cancer-associated VTE from 2 multicentre randomized controlled trials comparing LMWH with vitamin K antagonists (VKA) (ClotCant group). In these studies the stage of disease was not separated by exact TNM classification, rather patients were classified as stage I, II (no metastasis) versus III, IV (metastasis). As such, we redid our derivation model with stage I and II grouped together, which gave this variable a score of – 1. This resulted in a prediction rule which gave a recurrence risk that no longer clearly dichotomized risk; rather gave a low, intermediate, and high risk groups. As in our derivation study, we evaluated patients' risk of recurrence regardless of type of anticoagulant use (VKA or LMWH). Results: Of 819 patients, 86 (10.5%) presented with a VTE recurrence during the anticoagulation period. When we applied our derivation rule in this population, we were able to demonstrate a significant difference in VTE recurrence risk dependent on gender, primary tumour site, stage and history of prior VTE. Patients with a score < 0 have low risk (5.1%) for VTE recurrence and this represented 19% of the patient population; patients with a score of 0 had a intermediate risk (9.8%) and this represented 42% of patients; a score ≥ 1 was high risk (13.9%), occurring in 38% of the population. Dichotomizing the results gave a recurrence risk of 8% in patients with a score ≤ 0 and a 15.2% recurrence risk with a score > 0. Conclusion: the validation dataset suggests reproducibility of our model. The dichotomized score is less discriminatory than our original model suggesting an advantage to classifying patients tumour stage as TNM stage I versus stage II, III and IV. Unfortunately, we could not test this hypothesis with the ClotCant dataset. Our model appears to differentiate risk for recurrence and should be utilized in treatment trials: attempting novel treatment strategies in high risk patients since LMWH alone does not seem to be enough; and using the less costly typical “LMWH followed by oral anticoagulants” in the low risk population to evaluate whether VKA can be as safe and effective as long term LMWH. Disclosures: Lee: Eisai: Research Funding; Sanofi Aventis: Consultancy, Honoraria; Leo Pharma: Consultancy; Pfizer: Consultancy, Honoraria; Bayer: Honoraria; Boehringer Ingelheim: Consultancy, Honoraria, Speakers Bureau.

Wells PS, Anderson DR, Rodger M, et al . Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. N Engl J Med 2003;349:1227–35. [OpenUrl][1][CrossRef][2][PubMed][3][Web of Science][4] Q In outpatients with suspected deep venous thrombosis (DVT), does the use of D-dimer testing safely reduce the need for venous ultrasonographic imaging (VUI) and rule out DVT on the day of presentation? Clinical impact ratings GP/FP/Primary care ★★★★★☆☆ IM/Ambulatory care ★★★★★★☆ Haematology ★★★★★★☆ ### ![Graphic][5] Design: randomised controlled trial. ### ![Graphic][6] Allocation: concealed.* ### ![Graphic][7] Blinding: blinded (ultrasonographers, technicians who measured D-dimer concentrations, and outcome assessors).* ### ![Graphic][8] Follow up period: 3 months. ### ![Graphic][9] Setting: Thrombosis units and emergency departments of 5 academic health centres in Canada. ### ![Graphic][10] Patients: 1096 outpatients (mean age 58 y, 58% women) who had suspected lower extremity DVT. Exclusion criteria included refusal or inability to consent and geographic inaccessibility. ### ![Graphic][11] Intervention: patients were stratified by the application of a clinical model as “likely" or “unlikely” to have DVT and were subsequently allocated to D-dimer testing … [1]: {openurl}?query=rft.jtitle%253DNew%2BEngland%2BJournal%2Bof%2BMedicine%26rft.stitle%253DNEJM%26rft.issn%253D0028-4793%26rft.aulast%253DWells%26rft.auinit1%253DP.%2BS.%26rft.volume%253D349%26rft.issue%253D13%26rft.spage%253D1227%26rft.epage%253D1235%26rft.atitle%253DEvaluation%2Bof%2BD-Dimer%2Bin%2Bthe%2BDiagnosis%2Bof%2BSuspected%2BDeep-Vein%2BThrombosis%26rft_id%253Dinfo%253Adoi%252F10.1056%252FNEJMoa023153%26rft_id%253Dinfo%253Apmid%252F14507948%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [2]: /lookup/external-ref?access_num=10.1056/NEJMoa023153&link_type=DOI [3]: /lookup/external-ref?access_num=14507948&link_type=MED&atom=%2Febmed%2F9%2F3%2F89.atom [4]: /lookup/external-ref?access_num=000185488800005&link_type=ISI [5]: /embed/inline-graphic-1.gif [6]: /embed/inline-graphic-2.gif [7]: /embed/inline-graphic-3.gif [8]: /embed/inline-graphic-4.gif [9]: /embed/inline-graphic-5.gif [10]: /embed/inline-graphic-6.gif [11]: /embed/inline-graphic-7.gif

Source Citation Kovacs MJ, Rodger M, Anderson DR, et al. Comparison of 10-mg and 5-mg warfarin initiation nomograms together with low-molecular-weight heparin for outpatient treatment of acute veno...

Introduction Placenta-mediated pregnancy complications (PMPC) include pre-eclampsia, late pregnancy loss, placental abruption, and the small-for-gestational age (SGA) newborn. They are leading causes of maternal, fetal, and neonatal morbidity and mortality. Affected women are at an elevated risk of recurrence in subsequent pregnancies. We completed a pooled summary-based (i.e. study level) meta-analysis that strongly suggests that low-molecular-weight heparin (LMWH) reduces the risk of recurrent PMPCs. However, our study-level meta-analysis was limited by high clinical and statistical heterogeneity likely due to the inclusion of women with heterogeneous prior PMPCs and trial designs (e.g. single vs multi-center trials). To address these limitations, the trialists agreed to conduct an individual patient data meta-analysis to identify sources of heterogeneity including exploring which patients benefit from LMWH and which outcomes are prevented. Methods We conducted a systematic review to identify randomised controlled trials that were eligible to contribute individual patient data to a meta-analysis to evaluate the effectiveness of LMWH for reducing the risk of PMPC in women with prior PMPCs. The primary outcome was a composite of early-onset or severe pre-eclampsia, birth of an SGA newborn < 5th percentile, late pregnancy loss (> 20 weeks), or placental abruption leading to delivery. Individual patient data from eligible women were re-coded in a prescribed format and combined in a common dataset for analysis. All studies were assessed for risk of bias. Results Data from 1049 women in nine trials were analysed; Participants were mostly Caucasian (88%) with a mean age of 31.518 had thrombophilia. 525 women were randomised to LMWH and 524 to no LMWH. In our primary outcome analysis, LMWH did not significantly reduce the risk of recurrent PMPCs (LMWH 60/459 (13.1%) vs. no LMWH 92/449 (20.5%) p=0.1). Significant heterogeneity was noted between single center and multi-center trials. In multi-center trials, LMWH reduced HELLP (p=0.03) but none of the other secondary outcomes, whereas in single center trials LMWH reduced all of the secondary outcomes. In sub-group analysis, in multi-center trials LMWH reduced the primary outcome in women with prior abruption (p Conclusions In this individual patient data meta-analysis, LMWH does not appear to reduce the risk of recurrent PMPC in women with prior PMPC. Promising results suggest that women with prior abruption may benefit from LMWH but this should be replicated in future multi-center trials. PROSPERO registration:CRD42013006249 Table. Primary Analysis All Studies Multi-Center Studies Single Center Studies Composite outcome Risk difference (95% CI) N=908 -0.07 (-0.16, 0.01)p = 0.10 N=524 -0.01 (-0.11, 0.09) p = 0.89 N=384 -0.17 (-0.21, -0.13) p < .0001 Secondary Outcome Analyses Severe or Early Preeclampsia Risk difference (95% CI) N=946 -0.04 (-0.10, 0.02) p = 0.20 N=562 0.01 (-0.06, 0.07) p = 0.81 N=384 -0.11 (-0.16, -0.07) p 12 weeks or 1 >16 weeks) Risk difference (95% CI) N=245 0.001 (-0.11, 0.12) p = 0.98 N=0 Prior SGA < 10 Risk difference (95% CI) N=305 -0.12 (-0.25, 0.01) p = 0.08 N=203 -0.03 (-0.17, 0.10) p = 0.64 N=102 -0.29 (-0.38, -0.20) p Disclosures Rodger: Biomerieux: Honoraria, Research Funding. Off Label Use: Low Molecular Weight Heparin to prevent pregnancy complications. de Vries:Pfizer: Research Funding. Rey:Leo Pharma: Other: Travel Grant. Gris:Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Stago: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Leo Pharma: Consultancy, Speakers Bureau; LFB: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Baxter: Research Funding; BI: Speakers Bureau; Bayer: Speakers Bureau; BMS: Speakers Bureau. Schleussner:Bayer: Speakers Bureau; Pfizer: Research Funding, Speakers Bureau; Merck: Research Funding, Speakers Bureau. Middeldorp:GSK/Aspen: Research Funding; Bayer: Consultancy, Speakers Bureau; BI: Consultancy, Speakers Bureau; BMS: Consultancy, Research Funding, Speakers Bureau; Pfizer: Consultancy, Research Funding, Speakers Bureau; Daiichi-Sankyo: Consultancy, Speakers Bureau. Bates:Eli Lilly Canada: Other: I hold the Eli Lilly Canada/May Cohen Chair in Women's Health. Eli Lilly Canada provides unrestricted funding for partial salary support through this Chair. Eli Lilly Canada does not manufacture/distribute drugs relevant to the topic to be discussed..