Original Article
Safety of Withholding Heparin in Pregnant Women with a History of Venous Thromboembolism
N Engl J Med 2000; 343:1439-1444November 16, 2000
- Abstract
Background
Women with a history of venous thromboembolism may be at increased risk for venous thromboembolic events during pregnancy. In these women, the decision to give or withhold heparin in the antepartum period is controversial, because accurate estimates of the frequency of recurrent thromboembolic events if antepartum heparin is withheld are not available.
Methods
We prospectively studied 125 pregnant women with a single previous episode of venous thromboembolism. Antepartum heparin was withheld, but anticoagulant therapy was given for four to six weeks post partum. Our primary objective was to determine the rate of antepartum recurrence of venous thromboembolism. Laboratory studies were performed to identify thrombophilia in 95 women.
Results
Three of the 125 women (2.4 percent) had an antepartum recurrence of venous thromboembolism (95 percent confidence interval, 0.2 to 6.9 percent). There were no recurrences in the 44 women who had no evidence of thrombophilia and who also had a previous episode of thrombosis that was associated with a temporary risk factor. Among the 51 women with abnormal laboratory results or a previous episode of idiopathic thrombosis, or both, 3 (5.9 percent) had an antepartum recurrence of venous thromboembolism (95 percent confidence interval, 1.2 to 16.2 percent).
Conclusions
The risk of recurrent antepartum venous thromboembolism in women with a history of venous thromboembolism is low, and therefore routine antepartum prophylaxis with heparin is not warranted.
Media in This Article
Table 1
Recurrent Venous Thromboembolic Events during and after Pregnancy in 125 Women with Previous Venous Thromboembolism.Table 2
Risk Factors and Rate of Recurrent Venous Thromboembolic Events in 95 Women with Previous Venous Thromboembolism.Article Activity
- Article
Previous venous thromboembolism (a collective term for deep venous thrombosis and pulmonary embolism) is a recognized risk factor for venous thromboembolism in nonpregnant patients after anticoagulation therapy is discontinued.1 The risk diminishes with time after the initial event. The risk is higher if the past episode was unprovoked,2 and the risk may be higher if the past episode was associated with biochemical abnormalities indicating thrombophilia than if it was associated with a reversible risk factor.3 Although infrequent, venous thromboembolism during pregnancy is an important cause of maternal death.4,5 Women with prior venous thromboembolism are believed to have a higher risk of venous thromboembolism in a subsequent pregnancy, but estimates of recurrence rates vary from 0 to 13 percent.
The higher estimate has prompted some authorities to recommend anticoagulant prophylaxis during pregnancy and during the postpartum period in women with prior venous thromboembolism.6-8 However, the risk is likely to be lower than previously suggested, because objective testing was rarely used to confirm the diagnosis of venous thromboembolism (resulting in an overestimate), and retrospective studies involved nonconsecutive patients,9,10 with the lower estimates coming from prospective studies.11-13 Anticoagulant therapy during pregnancy is problematic, because coumarins can cause embryopathy, and heparin, although safe for the fetus, is expensive and inconvenient and can cause bleeding6 and osteoporosis.14,15
In view of these considerations, and a recent overview that claimed that fatal pulmonary embolism as the initial manifestation of recurrence is rare, particularly in patients with good cardiopulmonary reserve,16 the routine use of heparin prophylaxis in pregnant women with previous venous thromboembolism should be challenged. We performed a prospective cohort study to evaluate the safety of withholding antepartum heparin prophylaxis in women with a single previous episode of venous thromboembolism.
Methods
Patients and Clinical Tests
We conducted a multicenter, prospective cohort study of consecutive, eligible women between July 1994 and September 1998. To be eligible for the study, women had to be enrolled before 20 weeks' gestation and have a history of a single episode of deep-vein thrombosis of the leg diagnosed by either compression ultrasonography or venography, or pulmonary embolism diagnosed by either lung scintigraphy or pulmonary angiography. Women were excluded if they had any of the following: known thrombophilia (deficiency of antithrombin, protein C, or protein S, or presence of antiphospholipid antibodies, the factor V Leiden mutation or the prothrombin G20210A mutation), an ongoing need for anticoagulant therapy, or venous thromboembolism within three months before the current pregnancy. All women underwent bilateral compression ultrasonography of the deep veins on entry into the study. Antithrombotic treatment was not administered ante partum. Within 24 hours after delivery, all the women were given 5000 or 7500 U of unfractionated heparin subcutaneously twice daily and a first dose of warfarin. Heparin treatment was discontinued at discharge, regardless of the international normalized ratio. Warfarin was given for four to six weeks post partum in doses adjusted to achieve a target international normalized ratio of 2.0 to 3.0. The women were seen in the clinic when warfarin treatment was discontinued, and there was follow-up by telephone at three months post partum.
Clinical follow-up was conducted as follows. Women who had symptoms or signs of deep-vein thrombosis during pregnancy underwent serial compression ultrasonography of the proximal veins, and the results were compared with the base-line images. If the base-line images were normal and there was a noncompressible segment, deep-vein thrombosis was diagnosed.17 If the base-line compression ultrasonogram was abnormal and no new changes were found, ultrasonography was repeated in seven days. If a new noncompressible segment was identified, it was considered diagnostic of recurrence. If serial testing raised the suspicion of a new noncompressible segment, venography with lead shielding of the fetus was performed; a persistent intraluminal defect was considered diagnostic of recurrence. Women with symptoms or signs of pulmonary embolism underwent ventilation–perfusion lung scanning. Pulmonary embolism was ruled out if the perfusion scan was normal and was diagnosed if the result was interpreted as indicating a high probability of pulmonary embolism. For other, nondiagnostic lung-scan patterns, the clinician had the option of performing serial compression ultrasonography or pulmonary angiography with appropriate shielding of the fetus. In all cases, when deep-vein thrombosis or pulmonary embolism was suspected and ruled out, anticoagulant therapy was withheld. All cases of suspected symptomatic recurrence were assessed by an independent central adjudication committee.
Blood samples were obtained from 95 women on entry into the study. Plasma was separated by centrifugation and stored at –70°C until assayed; peripheral-blood leukocytes were stored for analysis for possible mutations. Assays for factor V Leiden,18 the prothrombin G20210A mutation,19 protein C,20 protein S,21 antithrombin,22 anticardiolipin antibodies,23 and lupus anticoagulant24-26 were performed in a central laboratory. For factor V Leiden and the prothrombin G20210A mutation, the test results were based on genetic analysis that determined whether any abnormal genes were present. The criteria for the diagnosis of deficiencies were less than 66 percent of normal activity for protein C, less than 24 percent for free protein S antigen, and less than 80 percent for antithrombin activity. Lupus anticoagulant was considered to be present if the lupus-sensitive activated partial-thromboplastin time (Diagnostica Stago, Asnières, France) and dilute Russell's-viper venom time (DRVV, American Diagnostica, Greenwich, Conn.) were abnormal. Abnormal results were confirmed by either hexagonal phospholipid (Staclot LA, Diagnostica Stago) or DRVV Confirm (American Diagnostica) tests. Anticardiolipin antibodies were considered to be present when the serum antibody concentrations exceeded five standard deviations above the mean (Anticardiolipin Test, Readds, Westminister, Colo.). Since the plasma free concentration of protein S is reduced in pregnant women, the measurements were repeated at least three months after the discontinuation of postpartum treatment with coumarins in the women whose concentrations were low during pregnancy. Only women with persistently low concentrations were considered to have inherited protein S deficiency. The tests were not performed until the trial was completed. The protocol was approved by the institutional review boards of the participating centers, and written informed consent was obtained from all study subjects.
Statistical Analysis
We calculated 95 percent confidence intervals for each point estimate of clinical events. Odds ratios and the corresponding 95 percent confidence intervals were calculated with Confidence Interval Analysis software (version 1.1, British Medical Journal, London). We anticipated a 6 percent rate of recurrence of antepartum venous thromboembolism, and on the basis of this estimate, we sought to enroll a sample large enough to exclude the possibility that the true recurrence rate was 10 percent or more. Thus, if the upper limit of the 95 percent confidence interval was less than 10 percent, it would be reasonable to recommend withholding antepartum heparin prophylaxis. We initially planned to enroll 250 women, but we stopped the trial after enrolling 125 women because the single planned interim analysis ruled out a true recurrence rate of 10 percent. We did not calculate a statistical penalty when we stopped the study early, and the 95 percent confidence intervals are therefore uncorrected and thus marginally narrower than they should be.
Results
One hundred thirty-three women met the inclusion criteria, of whom six were subsequently excluded; five had known thrombophilia, and one had deep-vein thrombosis within three months of entry into the study. Of the 127 eligible women, 2 refused consent. The mean (±SD) age of the women was 30±5 years, and the duration of pregnancy at enrollment was 15±6 weeks. There were 131 previous episodes of venous thromboembolism (six women had previously had simultaneous deep-vein thrombosis and pulmonary embolism). Of the initial episodes, 92 were deep-vein thrombosis (25 idiopathic and 67 associated with a temporary risk factor) and 39 were pulmonary embolism (18 idiopathic and 21 associated with a temporary risk factor). The temporary risk factors for the initial episode of venous thromboembolism in the women were pregnancy in 31 women, oral-contraceptive use in 20, surgery in 16, trauma in 12, immobility in 4, and chemotherapy in 1. In women with an initial episode that was idiopathic, the mean interval between the initial event and entry into the study was 4±4 years.
There were three episodes of recurrent antepartum venous thromboembolism (2.4 percent; 95 percent confidence interval, 0.2 to 6.9 percent) (Table 1Table 1
Recurrent Venous Thromboembolic Events during and after Pregnancy in 125 Women with Previous Venous Thromboembolism.). Two women had antepartum deep-vein thrombosis: one had a proximal deep-vein thrombosis at 29 weeks' gestation, and the other had deep-vein thrombosis in the calf at 28 weeks. There was a single case of pulmonary embolism at nine weeks' gestation. These three women were treated with low-molecular-weight heparin for the remainder of their pregnancies.There were also three episodes of postpartum deep-vein thrombosis: one occurred 2 days after a complicated missed abortion with hemorrhage at 11 weeks of gestation, and the other two occurred at 3 and 8 weeks post partum. All three women were treated with anticoagulant therapy. No woman had a postpartum recurrence while receiving warfarin, and the mean duration of warfarin prophylaxis was 33 days. However, one of the three women who had a postpartum recurrence might have benefited from a longer course of anticoagulant therapy, because the recurrence occurred two weeks after she stopped taking warfarin. Neither of the other two women who had a postpartum recurrence received postpartum warfarin; warfarin was withheld in one woman because of uterine hemorrhage, and the other refused warfarin and was given 12,500 U of unfractionated heparin twice daily subcutaneously without laboratory monitoring. No woman had any bleeding while receiving anticoagulant therapy.
There were nine episodes of suspected pulmonary embolism (all investigated by ventilation–perfusion lung scanning) in nine women, of which one was objectively confirmed. Suspected deep-vein thrombosis was investigated 18 times in 18 women and was objectively confirmed in 5 women. There were no episodes of fatal pulmonary embolism. Of the 41 women with an initial episode of idiopathic venous thromboembolism, 4 had recurrent venous thromboembolism, as compared with 2 recurrences among the 84 women whose initial venous thromboembolic event was not idiopathic (odds ratio, 4.4; 95 percent confidence interval, 0.1 to 36.0). Recurrence rates for these women are shown in Table 2Table 2
Risk Factors and Rate of Recurrent Venous Thromboembolic Events in 95 Women with Previous Venous Thromboembolism..Of the 95 women from whom blood was taken on entry into the study, 48 (51 percent) had one or more abnormalities. Of the 30 women who did not have blood samples taken, none had a recurrence. There were 58 abnormal test results in the 48 women who had at least 1 abnormal result: low plasma concentrations of free protein S in 30 women, heterozygosity for factor V Leiden in 11, heterozygosity for the prothrombin G20210A mutation in 7, antithrombin deficiency in 3, protein C deficiency in 3, lupus anticoagulant in 2, and anticardiolipin antibodies in 2. None of the women were homozygous for factor V Leiden or the prothrombin G20210A mutation.
Plasma concentrations of free protein S are often low during the second and third trimesters of pregnancy.27,28 Only 1 of the 30 women with low plasma concentrations of free protein S (Patient 6 in Table 1) had true protein S deficiency on testing during follow-up; she had a recurrent deep-vein thrombosis post partum. None of the 29 women with transiently low plasma concentrations of free protein S had a recurrence (Table 3Table 3
Abnormal Test Results and Risk of Antepartum and Postpartum Recurrent Venous Thromboembolism in 95 Women with Previous Venous Thromboembolism.).Aside from the transiently low plasma concentrations of free protein S during pregnancy, there were 29 abnormal test results in 25 of the 95 women from whom blood was drawn (26 percent) (Table 3). Of these women, 22 had a single abnormal test result and 3 had multiple abnormal results. One woman had factor V Leiden, the prothrombin G20210A mutation, and protein C deficiency; one had both anticardiolipin antibodies and lupus anticoagulant; and one had factor V Leiden and protein C deficiency. Among these 25 women with abnormal test results, 4 had recurrent venous thromboembolism, as compared with 2 of the 70 women with normal test results (odds ratio, 6.5; 95 percent confidence interval, 0.8 to 56.3). Of the test abnormalities, factor V Leiden was associated with the highest odds ratio (Table 3).
Fifty-one women had an abnormal laboratory result, a previous episode of idiopathic thrombosis, or both. Three of these women (5.9 percent; 95 percent confidence interval, 1.2 to 16.2 percent) had an antepartum recurrence of venous thromboembolism. In contrast, there were no recurrences among the 44 women with normal laboratory results and a previous episode that was associated with a temporary risk factor.
Discussion
We found that women with a single previous episode of venous thromboembolism had a low rate of recurrent antepartum events during a subsequent pregnancy. The three antepartum events that occurred correspond to a rate of recurrence of 4.0 percent per patient-year of follow-up. This risk is similar to that among patients who have been treated for venous thromboembolism associated with a temporary risk factor, a subgroup with a lower-than-average risk of recurrence.29,30
The strengths of our study are that it was prospective, that only women with previous, objectively documented venous thromboembolism were eligible, and that there was independent, central adjudication of clinical events. Its limitations are as follows. We did not achieve our estimated sample size because we stopped the study early after a planned interim analysis. However, the upper limit of the 95 percent confidence interval for antepartum recurrence of venous thromboembolism was 6.9 percent, a value that reliably excludes a true rate of 10 percent.
In addition, our estimates of risk factors for the recurrence of venous thromboembolism were based on subgroup analyses, but they are likely to be accurate because they are consistent with the results of studies in nonpregnant patients. For example, none of the 44 women in our study who had normal test results and an initial episode of venous thromboembolism associated with a temporary risk factor had a recurrence (Table 2). In contrast, women with an initial episode of idiopathic venous thromboembolism and those with an abnormal test result on screening for thrombophilia (especially factor V Leiden) appeared to be at increased risk for recurrence. However, for each calculation except that for factor V Leiden, the lower limit of the 95 percent confidence interval for the odds ratio was less than 1.0 (Table 3).
Another limitation is that the selection of women who had had one prior episode of venous thromboembolism and the exclusion of women who had had an episode of venous thromboembolism within three months before pregnancy means our results are not generalizable to pregnant women with multiple prior thrombotic events or a very recent event.
Finally, although there were no fatal cases of pulmonary embolism, even a slight increase in fatal recurrences would be unacceptable. However, in a recent study, fatal pulmonary embolism was a rare manifestation of recurrence, particularly in the absence of cardiopulmonary disease and premonitory symptoms.16 We emphasized the need for prompt investigation of symptoms of deep-vein thrombosis and pulmonary embolism to women in this study.
In summary, the low rate of recurrence in our study challenges the belief that all pregnant women with previous venous thromboembolism should receive antepartum heparin prophylaxis. However, we recommend postpartum anticoagulant therapy with warfarin because of its safety, convenience, and low cost. In pregnant women with previous venous thromboembolism who have not been tested for thrombophilia, we recommend such testing ante partum. In particular, given the high prevalence of factor V Leiden among the women in this study (11.6 percent) and the association between factor V Leiden and recurrence, testing for this abnormality is important. Conversely, we do not recommend that plasma free protein S be measured ante partum, because abnormal results are common and do not predict recurrence of thromboembolism.
None of the 44 women with a temporary risk factor and normal blood-test results had a recurrence, strongly suggesting that they need not receive antepartum heparin prophylaxis. In the other three subgroups of women, in whom the recurrence rates were higher, we recommend offering the choice of antepartum heparin or regular follow-up examinations.
Supported by a grant (NA2857) from the Heart and Stroke Foundation of Canada. Drs. Ginsberg and Weitz are Career Investigators of the Heart and Stroke Foundation of Ontario. Dr. Kearon is a Research Scholar of the Heart and Stroke Foundation of Canada.
Source Information
From the McMaster University Medical Centre, Hamilton, Ont. (P.B.-E., J.S.G., M.G., J.H., C.K., J.I.W.); Monash Medical Centre, Clayton, Vic., Australia (R.B.); Sunnybrook Health Science Centre, Toronto (W.G.); London Health Science Centre, London, Ont. (M.K.); Queen Elizabeth II Health Science Centre, Halifax, N.S. (K.S.R.); Hôpital du Sacré-Coeur de Montréal, Montreal (R.W.); and the Centre Hospitalier de l'Université du Québec–St. François d'Assise, Quebec, Que. (G.C.) — all in Canada.
Address reprint requests to Dr. Ginsberg at the McMaster University Medical Centre, 1200 Main St. W, HSC-3X28, Hamilton, ON L8N 3Z5, Canada, or at ginsbrgj@fhs.mcmaster.ca.
The other contributors to this study are listed in the Appendix.
Appendix
The following investigators contributed to this study: P. Stevens, J.A. Bennett, J. Douketis, M. Johnston, T. Finch, and L. Liberale (Hamilton, Ont., Canada); B. Morrow, W.F. Brien, and B. Palmer (London, Ont., Canada); M. Fairhurst-Vaughan, A. MacLellan, K. Scott, C. Gordon, and L. Gray (Halifax, N.S., Canada); J. Poulin (Québec, Que., Canada); P. Ockelford, R. North, and A. Bennett (Auckland, New Zealand); P. Prandoni (Padua, Italy); K. Rosene Montella and D. Bagdasarian (Providence, R.I.); P. Wells and P. Florack (Ottawa, Ont., Canada); R. Koopman (Amsterdam); J. Kassis and S. Bournais (Montreal); and W.S. Chan (Toronto).
- References
References
1
Anderson FA Jr ,Wheeler HB ,Goldberg RJ , et al. A population-based perspective of the hospital incidence and case-fatality rates of deep vein thrombosis and pulmonary embolism: the Worcester DVT Study. Arch Intern Med 1991;151:933-938
CrossRef | Web of Science | Medline2
Prandoni P ,Lensing AWA ,Buller HR , et al. Deep-vein thrombosis and the incidence of subsequent symptomatic cancer. N Engl J Med 1992;327:1128-1133
Full Text | Web of Science | Medline3
Lane DA ,Mannucci PM ,Bauer KA , et al. Inherited thrombophilia. Thromb Haemost 1996;76:824-834
Web of Science | Medline4
Sachs BP ,Brown DAJ ,Driscoll SG , et al. Maternal mortality in Massachusetts: trends and prevention. N Engl J Med 1987;316:667-672
Full Text | Web of Science | Medline5
Kaunitz AM ,Hughes JM ,Grimes DA ,Smith JC ,Rochat RW ,Kafrissen ME . Causes of maternal mortality in the United States. Obstet Gynecol 1985;65:605-612
Web of Science | Medline6
Ginsberg JS ,Hirsh J . Use of antithrombotic agents during pregnancy. Chest 1998;114:Suppl:524S-530S
CrossRef | Web of Science | Medline7
Maternal and Neonatal Haemostasis Working Party of the Haemostasis and Thrombosis Task
CrossRef | Web of Science | Medline8
Colvin BT ,Barrowcliffe TW . The British Society for Haematology guidelines on the use and monitoring of heparin 1992: second revision. J Clin Pathol 1993;46:97-103
CrossRef | Web of Science | Medline9
Tengborn L ,Bergqvist D ,Matzsch T ,Bergqvist A ,Hedner U . Recurrent thromboembolism in pregnancy and puerperium: is there a need for thromboprophylaxis? Am J Obstet Gynecol 1989;160:90-94
Web of Science | Medline10
Badaracco MA ,Vessey MP . Recurrence of venous thromboembolic disease and use of oral contraceptives. BMJ 1974;1:215-217
CrossRef | Web of Science | Medline11
Howell R ,Fidler J ,Letsky E ,de Swiet M . The risks of antenatal subcutaneous heparin prophylaxis: a controlled trial. Br J Obstet Gynaecol 1983;90:1124-1128
CrossRef | Medline12
Lao TT ,de Swiet M ,Letsky E ,Walters BNJ . Prophylaxis of thromboembolism in pregnancy: an alternative. Br J Obstet Gynaecol 1985;92:202-206
CrossRef | Medline13
de Swiet M ,Floyd E ,Letsky E . Low risk of recurrent thromboembolism in pregnancy. Br J Hosp Med 1987;38:264-264
Web of Science | Medline14
Dahlman TC . Osteoporotic fractures and the recurrence of thromboembolism during pregnancy and the puerperium in 184 women undergoing thromboprophylaxis with heparin. Am J Obstet Gynecol 1993;168:1265-1270
Web of Science | Medline15
Dahlman TC ,Lindvall N ,Hellgren M . Osteopenia in pregnancy during long-term heparin treatment: a radiological study post partum. Br J Obstet Gynaecol 1990;97:221-228
CrossRef | Medline16
Douketis J ,Kearon C ,Bates S ,Duku EK ,Ginsberg JS . Risk of fatal pulmonary embolism in patients with treated venous thromboembolism. JAMA 1998;279:458-462
CrossRef | Web of Science | Medline17
Lensing AWA ,Prandoni P ,Brandjes D , et al. Detection of deep-vein thrombosis by real-time B-mode ultrasonography. N Engl J Med 1989;320:342-345
Full Text | Web of Science | Medline18
Bertina RM ,Koeleman BP ,Koster T , et al. Mutation in blood coagulation factor V associated with resistance to activated protein C. Nature 1994;369:64-67
CrossRef | Web of Science | Medline19
Poort SR ,Rosendaal FR ,Reitsma PH ,Bertina RM . A common genetic variation in the 3'-untranslated region of the prothrombin gene is associated with elevated plasma prothrombin levels and an increase in venous thrombosis. Blood 1996;88:3698-3703
Web of Science | Medline20
Martinoli JL ,Stocker K . Fast functional protein C assay using Protac, a novel protein C activator. Thromb Res 1986;43:253-264
CrossRef | Web of Science | Medline21
Deutz-Terlouw PP ,Ballering L ,van Wijngaarden A ,Bertina RM . Two ELISA's for measurement of protein S, and their use in the laboratory diagnosis of protein S deficiency. Clin Chim Acta 1990;186:321-334
CrossRef | Web of Science | Medline22
Andersson N-E ,Menschik M ,van Voorthuizen H . New chromogenic AT III activity kit which is insensitive to heparin cofactor II and designed for use on automated instruments. Thromb Haemost 1991;65:912-912 abstract.
Web of Science23
Loizou S ,McCrea JD ,Rudge AC ,Reynolds R ,Boyle CC ,Harris EN . Measurement of anti-cardiolipin antibodies by an enzyme-linked immunosorbent assay (ELISA): standardization and quantification of results. Clin Exp Immunol 1985;62:738-745
Web of Science | Medline24
Proctor RR ,Rapaport SI . The partial thromboplastin time with kaolin: a simple screening test for first stage plasma clotting factor deficiencies. Am J Clin Pathol 1961;36:212-219
Web of Science | Medline25
Triplett DA ,Barna LK ,Unger GA . A hexagonal (II) phase phospholipid neutralization assay for lupus anticoagulant identification. Thromb Haemost 1993;70:787-793
Web of Science | Medline26
Thiagarajan P ,Pengo V ,Shapiro SS . The use of the dilute Russell viper venom time for the diagnosis of lupus anticoagulants. Blood 1986;68:869-874
Web of Science | Medline27
Faught W ,Garner P ,Jones G ,Ivey B . Changes in protein C and protein S levels in normal pregnancy. Am J Obstet Gynecol 1995;172:147-150
CrossRef | Web of Science | Medline28
Warwick R ,Hutton RA ,Goff L ,Letsky E ,Heard M . Changes in protein C and free protein S during pregnancy and following hysterectomy. J R Soc Med 1989;82:591-594
Web of Science | Medline29
Schulman S ,Rhedin A-S ,Lindmarker P , et al. A comparison of six weeks with six months of oral anticoagulant therapy after a first episode of venous thromboembolism. N Engl J Med 1995;332:1661-1665
Full Text | Web of Science | Medline30
Levine MN ,Hirsh J ,Gent M , et al. Optimal duration of oral anticoagulant therapy: a randomized trial comparing four weeks with three months of warfarin in patients with proximal deep vein thrombosis. Thromb Haemost 1995;74:606-611
Web of Science | Medline
- Citing Articles (116)
Citing Articles
1
James A. Airoldi. 2011. Venous thromboembolism and anticoagulation. , 215-226.
CrossRef2
James A. Airoldi. 2011. Inherited thrombophilia. , 207-214.
CrossRef3
Ghada Bourjeily, Hanan Khalil, Christina Raker, Susan Martin, Pauline Auger, Michel Chalhoub, Lucia Larson, Margaret Miller. (2011) Outcomes of Negative Multidetector Computed Tomography with Pulmonary Angiography in Pregnant Women Suspected of Pulmonary Embolism. Lung
CrossRef4
Julia A.M. Anderson, Jeffrey I. Weitz. (2011) Hypercoagulable States. Critical Care Clinics 27:4, 933-952
CrossRef5
Shannon M. Bates. (2011) Pregnancy-Associated Venous Thromboembolism: Prevention and Treatment. Seminars in Hematology 48:4, 271-284
CrossRef6
Claire McLINTOCK, Tim BRIGHTON, Sanjeev CHUNILAL, Gus DEKKER, Nolan McDONNELL, Simon McRAE, Peter MULLER, Huyen TRAN, Barry N.J. WALTERS, Laura YOUNG. (2011) Recommendations for the prevention of pregnancy-associated venous thromboembolism. Australian and New Zealand Journal of Obstetrics and Gynaecologyno-no
CrossRef7
, , V. Regitz-Zagrosek, C. Blomstrom Lundqvist, C. Borghi, R. Cifkova, R. Ferreira, J.-M. Foidart, J. S. R. Gibbs, C. Gohlke-Baerwolf, B. Gorenek, B. Iung, M. Kirby, A. H. E. M. Maas, J. Morais, P. Nihoyannopoulos, P. G. Pieper, P. Presbitero, J. W. Roos-Hesselink, M. Schaufelberger, U. Seeland, L. Torracca, , J. Bax, A. Auricchio, H. Baumgartner, C. Ceconi, V. Dean, C. Deaton, R. Fagard, C. Funck-Brentano, D. Hasdai, A. Hoes, J. Knuuti, P. Kolh, T. McDonagh, C. Moulin, D. Poldermans, B. A. Popescu, Z. Reiner, U. Sechtem, P. A. Sirnes, A. Torbicki, A. Vahanian, S. Windecker, , H. Baumgartner, C. Deaton, C. Aguiar, N. Al-Attar, A. A. Garcia, A. Antoniou, I. Coman, U. Elkayam, M. A. Gomez-Sanchez, N. Gotcheva, D. Hilfiker-Kleiner, R. G. Kiss, A. Kitsiou, K. T. S. Konings, G. Y. H. Lip, A. Manolis, A. Mebaaza, I. Mintale, M.-C. Morice, B. J. Mulder, A. Pasquet, S. Price, S. G. Priori, M. J. Salvador, A. Shotan, C. K. Silversides, S. O. Skouby, J.-I. Stein, P. Tornos, N. Vejlstrup, F. Walker, C. Warnes. (2011) ESC Guidelines on the management of cardiovascular diseases during pregnancy: The Task Force on the Management of Cardiovascular Diseases during Pregnancy of the European Society of Cardiology (ESC). European Heart Journal
CrossRef8
2011. , 17-68.
CrossRef9
PELLE G. LINDQVIST, KATARINA BREMME, MARGARETA HELLGREN, . (2011) Efficacy of obstetric thromboprophylaxis and long-term risk of recurrence of venous thromboembolism. Acta Obstetricia et Gynecologica Scandinavica 90:6, 648-653
CrossRef10
E.M. Battinelli, K.A. Bauer. (2011) Thrombophilias in Pregnancy. Hematology/Oncology Clinics of North America 25:2, 323-333
CrossRef11
Margaret A. Miller, Michel Chalhoub, Ghada Bourjeily. (2011) Peripartum Pulmonary Embolism. Clinics in Chest Medicine 32:1, 147-164
CrossRef12
Emily Jackson, Kathryn M. Curtis, Mary E. Gaffield. (2011) Risk of Venous Thromboembolism During the Postpartum Period. Obstetrics & Gynecology 117:3, 691-703
CrossRef13
J. E. ROETERS VAN LENNEP, E. MEIJER, F. J. C. M. KLUMPER, J. M. MIDDELDORP, K. W. M. BLOEMENKAMP, S. MIDDELDORP. (2011) Prophylaxis with low-dose low-molecular-weight heparin during pregnancy and postpartum: is it effective?. Journal of Thrombosis and Haemostasis 9:3, 473-480
CrossRef14
Emily Jackson. (2011) Controversies in postpartum contraception: When is it safe to start oral contraceptives after childbirth?. Thrombosis Research 127, S35-S39
CrossRef15
Hyun Sun Won, Do Yi Kim, Moon Seok Yang, Sung Ja Lee, Hyun-Ho Shin, Jeong Bae Park. (2011) Pregnancy-Induced Hypertension, But Not Gestational Diabetes Mellitus, Is a Risk Factor for Venous Thromboembolism in Pregnancy. Korean Circulation Journal 41:1, 23
CrossRef16
Wee Shian Chan. (2010) Venous thromboembolism in pregnancy. Expert Review of Cardiovascular Therapy 8:12, 1731-1740
CrossRef17
M. Rodger. (2010) Evidence Base for the Management of Venous Thromboembolism in Pregnancy. Hematology 2010:1, 173-180
CrossRef18
Paul E. Marik. (2010) Venous Thromboembolism in Pregnancy. Clinics in Chest Medicine 31:4, 731-740
CrossRef19
Julia A.M. Anderson, Jeffrey I. Weitz. (2010) Hypercoagulable States. Clinics in Chest Medicine 31:4, 659-673
CrossRef20
Marc A. Rodger, Genevieve Le Templier. 2010. Anticoagulant Therapy During Pregnancy and Gynecology. , 111-152.
CrossRef21
Trevor Baglin. 2010. Heritable Thrombophilia. , 872-887.
CrossRef22
S. C. CHRISTIANSEN, W. M. LIJFERING, F. M. HELMERHORST, F. R. ROSENDAAL, S. C. CANNEGIETER. (2010) Sex difference in risk of recurrent venous thrombosis and the risk profile for a second event. Journal of Thrombosis and Haemostasis 8:10, 2159-2168
CrossRef23
Donna Dizon-Townson. 2010. Thromboembolic Disease. , 283-307.
CrossRef24
Chiara Benedetto, Luca Marozio, Anna Maria Tavella, Loredana Salton, Sara Grivon, Francesca Di Giampaolo. (2010) Coagulation disorders in pregnancy: acquired and inherited thrombophilias. Annals of the New York Academy of Sciences 1205:1, 106-117
CrossRef25
Alan Peaceman. 2010. Thromboembolism. , 210-215.
CrossRef26
Catherine Nelson-Piercy, Ian Greer. 2010. Thromboembolic Disease in Pregnancy. , 82-100.
CrossRef27
Martin N. Montoro. 2010. Venous Thromboembolism and Inherited Thrombophilias. , 117-126.
CrossRef28
Marc A. Rodger, Michael Paidas, Lawrence Tsen, Joanne Douglas. 2010. Thrombophilias and Pregnancy. , 101-117.
CrossRef29
Sarah M. Davis, D. Ware Branch. (2010) Thromboprophylaxis in Pregnancy: Who and How?. Obstetrics and Gynecology Clinics of North America 37:2, 333-343
CrossRef30
Rebecca Tooher, Simon Gates, Therese Dowswell, Lucy-Jane Davis, Rebecca Tooher. 2010. Prophylaxis for venous thromboembolic disease in pregnancy and the early postnatal period. .
CrossRef31
Isobel D. Walker. 2010. Obstetrics, Contraception, and Estrogen Replacement. , 247-257.
CrossRef32
Amir A Kuperman, Ron Hoffman, Benjamin Brenner. (2010) Managing thrombophilia during pregnancy. Expert Review of Obstetrics & Gynecology 5:3, 371-381
CrossRef33
Trevor Baglin, Elaine Gray, Mike Greaves, Beverley J. Hunt, David Keeling, Sam Machin, Ian Mackie, Mike Makris, Tim Nokes, David Perry, R. C. Tait, Isobel Walker, Henry Watson. (2010) Clinical guidelines for testing for heritable thrombophilia. British Journal of Haematology 149:2, 209-220
CrossRef34
Andra H. James. (2010) Pregnancy and thrombotic risk. Critical Care Medicine 38, S57-S63
CrossRef35
Ghada Bourjeily, Michael Paidas, Hanan Khalil, Karen Rosene-Montella, Marc Rodger. (2010) Pulmonary embolism in pregnancy. The Lancet 375:9713, 500-512
CrossRef36
Susan Murin, Kathryn Bilello, Lisa Moores, Aaron Holley. 2010. Gender Issues in Venous Thromboembolism. , 225-243.
CrossRef37
Annemarie E Fogerty, Jean M Connors. (2009) Management of inherited thrombophilia in pregnancy. Current Opinion in Endocrinology, Diabetes and Obesity 16:6, 464-469
CrossRef38
Federico Lussana, Francesco Dentali, Rosanna Abbate, Ernesto d'Aloja, Armando D'Angelo, Valerio De Stefano, Elena M. Faioni, Elvira Grandone, Cristina Legnani, Ida Martinelli, Paolo Simioni, Daniela Tormene. (2009) Screening for thrombophilia and antithrombotic prophylaxis in pregnancy: Guidelines of the Italian Society for Haemostasis and Thrombosis (SISET). Thrombosis Research 124:5, e19-e25
CrossRef39
Jeffrey I. Weitz. (2009) Prevention and treatment of venous thromboembolism during pregnancy. Catheterization and Cardiovascular Interventions 74:S1, S22-S26
CrossRef40
Yesim Dargaud, Lucia Rugeri, Marie Christine Vergnes, Brigitte Arnuti, Paula Miranda, Claude Negrier, Audrey Bestion, Hélène Desmurs-Clavel, Jacques Ninet, Pascal Gaucherand, Rene Charles Rudigoz, Michel Berland, Fabienne Champion, Marie Christine Trzeciak. (2009) A risk score for the management of pregnant women with increased risk of venous thromboembolism: a multicentre prospective study. British Journal of Haematology 145:6, 825-835
CrossRef41
Shannon M. Bates. 2009. Anticoagulation in Pregnancy. , 197-220.
CrossRef42
Marcelo P. Villa-Forte Gomes. (2009) Venous thromboembolism in pregnancy. Current Treatment Options in Cardiovascular Medicine 11:2, 104-113
CrossRef43
Nathan P. Clark, Thomas Delate, Daniel M. Witt, Suzanne Parker, Robert McDuffie. (2009) A descriptive evaluation of unfractionated heparin use during pregnancy. Journal of Thrombosis and Thrombolysis 27:3, 267-273
CrossRef44
Nina Raju, Shannon M Bates. (2009) Preventing thrombophilia-related complications of pregnancy. Expert Review of Hematology 2:2, 183-196
CrossRef45
Ingrid Pabinger. (2009) Thrombophilia and its impact on pregnancy. Thrombosis Research 123, S16-S21
CrossRef46
Scott M. Nelson. (2009) Prophylaxis of VTE in women – during assisted reproductive techniques. Thrombosis Research 123, S8-S15
CrossRef47
A. H. James. (2009) Pregnancy-associated thrombosis. Hematology 2009:1, 277-285
CrossRef48
Gorana Mitic, Ljubica Povazan, Aleksandar Lucic. (2009) Treatment of pregnancy related venous thromboembolism. Medicinski pregled 62:7-8, 346-351
CrossRef49
Joanne M. SAID, Shaun P. BRENNECKE, Eric K. MOSES, Susan P. WALKER, Paul T. MONAGLE, Janine CAMPBELL, Valerie J. BRYANT, Anthony J. BORG, John R. HIGGINS. (2008) The prevalence of inherited thrombophilic polymorphisms in an asymptomatic Australian antenatal population. Australian and New Zealand Journal of Obstetrics and Gynaecology 48:6, 536-541
CrossRef50
Andra H James. (2008) Thromboembolism in pregnancy: recurrence risks, prevention and management. Current Opinion in Obstetrics and Gynecology 20:6, 550-556
CrossRef51
Marik, Paul E., Plante, Lauren A., . (2008) Venous Thromboembolic Disease and Pregnancy. New England Journal of Medicine 359:19, 2025-2033
Full Text52
Christina M. Scifres, George A. Macones. (2008) The utility of thrombophilia testing in pregnant women with thrombosis: fact or fiction?. American Journal of Obstetrics and Gynecology 199:4, 344.e1-344.e7
CrossRef53
S. M. Nelson, I. A. Greer. (2008) The potential role of heparin in assisted conception. Human Reproduction Update 14:6, 623-645
CrossRef54
Michael P. Carson, Deborah Ehrenthal. (2008) Medical Issues from Preconception Through Delivery: A Roadmap for the Internist. Medical Clinics of North America 92:5, 1193-1225
CrossRef55
J. R. Lambert, S. K. Austin, D. Peebles, H. Cohen. (2008) Audit of the peri-delivery use of unfractionated heparin in women on therapeutic low-molecular weight heparin. British Journal of Haematology 142:3, 453-456
CrossRef56
W.S. Chan, M.E. Dixon. (2008) The “ART” of thromboembolism: A review of assisted reproductive technology and thromboembolic complications. Thrombosis Research 121:6, 713-726
CrossRef57
Mark H. Meissner, Thomas W. Wakefield, Enrico Ascher, Joseph A. Caprini, Anthony J. Comerota, Bo Eklof, David L. Gillespie, Lazar J. Greenfield, Aiwu Ruth He, Peter K. Henke, Anil Hingorani, Russell D. Hull, Craig M. Kessler, Robert D. McBane, Robert McLafferty. (2007) Acute venous disease: Venous thrombosis and venous trauma. Journal of Vascular Surgery 46:6, S25-S53
CrossRef58
Scott M Nelson, Ian A Greer. (2007) Thromboembolic events in pregnancy: pharmacological prophylaxis and treatment. Expert Opinion on Pharmacotherapy 8:17, 2917-2931
CrossRef59
Y.K. Agrawal, Hitesh Vaidya, Hardik Bhatt, Kuntal Manna, Pathik Brahmkshatriya. (2007) Recent advances in the treatment of thromboembolic diseases: Venous thromboembolism. Medicinal Research Reviews 27:6, 891-914
CrossRef60
Adam J. Duhl, Michael J. Paidas, Serdar H. Ural, Ware Branch, Holly Casele, Joan Cox-Gill, Sheri Lynn Hamersley, Thomas M. Hyers, Vern Katz, Randall Kuhlmann, Edith A. Nutescu, James A. Thorp, James L. Zehnder. (2007) Antithrombotic therapy and pregnancy: consensus report and recommendations for prevention and treatment of venous thromboembolism and adverse pregnancy outcomes. American Journal of Obstetrics and Gynecology 197:5, 457.e1-457.e21
CrossRef61
Jennifer Voke, Jane Keidan, Sue Pavord, Neil H. Spencer, Beverley J. Hunt, . (2007) The management of antenatal venous thromboembolism in the UK and Ireland: a prospective multicentre observational survey. British Journal of Haematology 139:4, 545-558
CrossRef62
Victor A. Rosenberg, Charles J. Lockwood. (2007) Thromboembolism in Pregnancy. Obstetrics and Gynecology Clinics of North America 34:3, 481-500
CrossRef63
John C. Smulian. (2007) Research on recurrent pregnancy complications: a clinician's perspective. Paediatric and Perinatal Epidemiology 21:s1, 19-23
CrossRef64
Scott M Nelson, Ian A Greer. (2007) Thrombophilia and maternal mortality: risk factors and preventive approaches. Expert Review of Obstetrics & Gynecology 2:4, 477-488
CrossRef65
Elizabeth Varga. (2007) Inherited Thrombophilia: Key Points for Genetic Counseling. Journal of Genetic Counseling 16:3, 261-277
CrossRef66
Andra H. James, Chad A. Grotegut, Leo R. Brancazio, Haywood Brown. (2007) Thromboembolism in Pregnancy: Recurrence and Its Prevention. Seminars in Perinatology 31:3, 167-175
CrossRef67
Rainer B Zotz, Andrea Gerhardt, Rüdiger E Scharf. (2007) Inherited thrombophilia and gestational venous thromboembolism. Women's Health 3:2, 215-225
CrossRef68
Thomas C. Krivak, Kristin K. Zorn. (2007) Venous Thromboembolism in Obstetrics and Gynecology. Obstetrics & Gynecology 109:3, 761-777
CrossRef69
Aba Barden-Maja, C. Jessica Dine, Laura M. Kosseim, Jodi Savitz, Daniel I. Steinberg. 2007. Selected Medical Problems Encountered During Pregnancy. , 444-491.
CrossRef70
S. M. Bates. (2007) Management of Pregnant Women with Thrombophilia or a History of Venous Thromboembolism. Hematology 2007:1, 143-150
CrossRef71
ROBERT M. SILVER, JENNIFER E. WARREN. (2006) Preconception Counseling for Women With Thrombophilia. Clinical Obstetrics and Gynecology 49:4, 906-919
CrossRef72
Valerio De Stefano, Ida Martinelli, Elena Rossi, Tullia Battaglioli, Tommaso Za, Pier Mannuccio Mannucci, Giuseppe Leone. (2006) The risk of recurrent venous thromboembolism in pregnancy and puerperium without antithrombotic prophylaxis. British Journal of Haematology 135:3, 386-391
CrossRef73
Farah Asghar, Paul Bowman. (2006) A clinical approach to the management of thrombosis in obstetrics. Part 1: screening and prophylaxis of venous thromboembolism. The Obstetrician & Gynaecologist 8:4, 215-221
CrossRef74
M COPPENS. (2006) Inherited Thrombophilias. Obstetrics and Gynecology Clinics of North America 33:3, 357-374
CrossRef75
S NELSON. (2006) Thrombophilia and the Risk for Venous Thromboembolism during Pregnancy, Delivery, and Puerperium. Obstetrics and Gynecology Clinics of North America 33:3, 413-427
CrossRef76
McDonald K. Horne, Donna Jo McCloskey. (2006) Factor V Leiden as a Common Genetic Risk Factor for Venous Thromboembolism. Journal of Nursing Scholarship 38:1, 19-25
CrossRef77
Andra H. James, David E. Abel, Leo R. Brancazio. (2006) Anticoagulants in Pregnancy. Obstetrical & Gynecological Survey 61:1, 59-69
CrossRef78
, , , , , , , , , , , , , , , , . (2005) Interdisziplinäre S2-Leitlinie. Diagnostik und Therapie der Bein- und Beckenvenenthrombose und der Lungenembolie. Intensivmedizin und Notfallmedizin 42:7, 552-565
CrossRef79
I. PABINGER, R. VORMITTAG. (2005) Thrombophilia and pregnancy outcomes. Journal of Thrombosis and Haemostasis 3:8, 1603-1610
CrossRef80
Dorothy-Jo Jordaan, Martinus Gerhardus Schoon, Philip Nel Badenhorst. (2005) Thrombophilia Screening in Pregnancy. Obstetrical & Gynecological Survey 60:6, 394-404
CrossRef81
I. PABINGER, H. GRAFENHOFER, A. KAIDER, P. A. KYRLE, P. QUEHENBERGER, C. MANNHALTER, K. LECHNER. (2005) Risk of pregnancy-associated recurrent venous thromboembolism in women with a history of venous thrombosis. Journal of Thrombosis and Haemostasis 3:5, 949-954
CrossRef82
Paul A Kyrle, Sabine Eichinger. (2005) Deep vein thrombosis. The Lancet 365:9465, 1163-1174
CrossRef83
A. E. M. Verdonkschot, W. L. E. Vasmel, S. Middeldorp, J. T. M. Schoot. (2005) Skin reactions due to low molecular weight heparin in pregnancy: a strategic dilemma. Archives of Gynecology and Obstetrics 271:2, 163-165
CrossRef84
Ian A. Greer. (2005) Venous thromboembolism and anticoagulant therapy in pregnancy. Gender Medicine 2, S10-S17
CrossRef85
R. M. Bauersachs. (2004) Therapie der Beinvenenthrombose. Der Internist 45:12, 1345-1355
CrossRef86
Richard H. White, Leslea A. Brickner, Kate A. Scannell. (2004) ICD-9-CM codes poorly indentified venous thromboembolism during pregnancy. Journal of Clinical Epidemiology 57:9, 985-988
CrossRef87
Jody L. Kujovich. (2004) Hormones and pregnancy: thromboembolic risks for women. British Journal of Haematology 126:4, 443-454
CrossRef88
Lisa Moores, Kathryn L Bilello, Susan Murin. (2004) Sex and gender issues and venous thromboembolism. Clinics in Chest Medicine 25:2, 281-297
CrossRef89
Beverley J Hunt, Mike Gattens, Munther Khamashta, Cathy Nelson-Piercy, Antonio Almeida. (2003) Thromboprophylaxis with unmonitored intermediate-dose low molecular weight heparin in pregnancies with a previous arterial or venous thrombotic event. Blood Coagulation & Fibrinolysis 14:8, 735-739
CrossRef90
B. Brenner. (2003) Antithrombotic prophylaxis for women with thrombophilia and pregnancy complications - Yes. Journal of Thrombosis and Haemostasis 1:10, 2070-2072
CrossRef91
Meyer-Michel Samama, Roberto A. Rached, Marie-Hélène Horellou, Sandro Aquilanti, Valérie G. Mathieux, Geneviève Plu-Bureau, Ismail Elalamy, Jacqueline Conard. (2003) Pregnancy-associated venous thromboembolism (VTE) in combined heterozygous factor V Leiden (FVL) and prothrombin (FII) 20210 A mutation and in heterozygous FII single gene mutation alone. British Journal of Haematology 123:2, 327-334
CrossRef92
(2003) Is recurrent venous thromboembolism more frequent in homozygous patients for the factor V Leiden mutation than in heterozygous patients?. Blood Coagulation & Fibrinolysis 14:6, 523-529
CrossRef93
Ingrid Pabinger, Helga Grafenhofer. (2003) Pregnancy-associated thrombosis. Wiener Klinische Wochenschrift 115:13-14, 482-484
CrossRef94
J. S. Ginsberg, S. M. Bates. (2003) Management of venous thromboembolism during pregnancy. Journal of Thrombosis and Haemostasis 1:7, 1435-1442
CrossRef95
K. A. Bauer. (2003) Management of thrombophilia. Journal of Thrombosis and Haemostasis 1:7, 1429-1434
CrossRef96
Marc A Rodger, Mark Walker, Philip S Wells. (2003) Diagnosis and treatment of venous thromboembolism in pregnancy. Best Practice & Research Clinical Haematology 16:2, 279-296
CrossRef97
Rainer B Zotz, Andrea Gerhardt, Rüdiger E Scharf. (2003) Inherited thrombophilia and gestational venous thromboembolism. Best Practice & Research Clinical Haematology 16:2, 243-259
CrossRef98
William M Hague, Gustaaf A Dekker. (2003) Risk factors for thrombosis in pregnancy. Best Practice & Research Clinical Haematology 16:2, 197-210
CrossRef99
Ian A Greer. (2003) Prevention of venous thromboembolism in pregnancy. Best Practice & Research Clinical Haematology 16:2, 261-278
CrossRef100
L BOWLES, H COHEN. (2003) Inherited thrombophilias and anticoagulation in pregnancy. Best Practice & Research Clinical Obstetrics & Gynaecology 17:3, 471-489
CrossRef101
I GREER. (2003) Inherited thrombophilia and venous thromboembolism. Best Practice & Research Clinical Obstetrics & Gynaecology 17:3, 413-425
CrossRef102
Robert F. Burrows. (2003) Haematological problems in pregnancy. Current Opinion in Obstetrics and Gynecology 15:2, 85-90
CrossRef103
Ian A Greer. (2003) Prevention and management of venous thromboembolism in pregnancy. Clinics in Chest Medicine 24:1, 123-137
CrossRef104
(2003) Genomic Medicine. New England Journal of Medicine 348:8, 759-760
Full Text105
Shannon M Bates. (2002) Treatment and prophylaxis of venous thromboembolism during pregnancy. Thrombosis Research 108:2-3, 97-106
CrossRef106
DONNA DIZON-TOWNSON. (2002) Pregnancy-Related Venous Thromboembolism. Clinical Obstetrics and Gynecology 45:2, 363-368
CrossRef107
Simon Gates, Peter Brocklehurst, Lucy-Jane Davis, Simon Gates. 2002. Prophylaxis for venous thromboembolic disease in pregnancy and the early postnatal period. .
CrossRef108
Fathima Paruk, Jack Moodley. (2001) Severe obstetric morbidity. Current Opinion in Obstetrics and Gynecology 13:6, 563-568
CrossRef109
Ian A. Greer. (2001) The acute management of venous thromboembolism in pregnancy. Current Opinion in Obstetrics and Gynecology 13:6, 569-575
CrossRef110
P GIBSON, K ROSENEMONTELLA. (2001) Anticoagulants. Best Practice & Research Clinical Obstetrics & Gynaecology 15:6, 847-861
CrossRef111
Isobel D Walker, M Greaves, F. E Preston. (2001) Investigation and management of heritable thrombophilia. British Journal of Haematology 114:3, 512-528
CrossRef112
R ANDRES, A MILES. (2001) VENOUS THROMBOEMBOLISM AND PREGNANCY. Obstetrics and Gynecology Clinics of North America 28:3, 613-630
CrossRef113
Kam Peters, MGAJ Wouters, Iro Nováková, EAP Steegers. (2001) Diepe veneuze trombose tijdens zwangerschap en kraambed. Huisarts en Wetenschap 44:8, 406-409
CrossRef114
I GREER, A THOMSON. (2001) Management of venous thromboembolism in pregnancy. Best Practice & Research Clinical Obstetrics & Gynaecology 15:4, 583-603
CrossRef115
Irene Hoesli, Frank Louwen, Wolfgang Holzgreve. (2001) Medical and obstetric problems complicating pregnancy. Current Opinion in Anaesthesiology 14:3, 299-306
CrossRef116
C. M. Schambeck. (2001) Recent Advances in Molecular Diagnostics of Thrombophilia. LaboratoriumsMedizin 25:7-8, 237-238
CrossRef
