| Objective:Pregnancy-associated venous thromboembolism is the main cause of maternal mortality in developed countries.The incidence rate is approximately 0.6-2.2 inches,which is 7-10 times that of non-pregnant women of the same age.The opinion of preventing pregnancy-associated venous thromboembolism is controversial.On one hand,thromboprophylaxis maybe necessary because of nonspecific clinical manifestations,rapid progresses and high mortality.On the other hand,pregnancy-associated venous thromboembolism is still a rare disease,and it is necessary to take the safety of mother and child into account.It is unclear that long-term thromboprophylaxis is ultimately benefical for both mother and fetus.Small amount of randomized controlled studies and cohort studies are used for meta-analysis to evaluate the efficacy and safety of low molecular weight heparin for the prevention of pregnancy-related venous thromboembolism in high-risk groups.Methods:Screening randomized controlled trials and well-designed cohort study that meet the inclusion exclusion criteria origin from Wanfang,CNKI,pubmed,medline,Embase,and cocharane library databases.Randomized controlled trials used the modified Jadad scale,while the cohort and case-control studies used the Newcastle-Ottawa Scale to evaluate the methodological quality of the included studies.The data were extracted from the full text.The system analysis software RevMan 5.3 provided by the Cochrane Collaboration was used to perform meta-analysis of the included studies,and the chi-square test was used to analyze the heterogeneity of the included studies.The funnel plot evaluate publication bias.Results:The incidence of pregnancy-associated VTE with low molecular weight heparin(LMWH)versus placebo was 0.16%and 0.68%respectively.RR ? 0.33;95%Cl:0.17-0.68;P = 0.002;The risk of postpartum VTE was 0.13%and 0.59%,RR = 0.31;95%Cl:0.14-0.69;P = 0.004.The risk ratio of VTE after thromboprophylaxis with prophylactic dose and therapeutic dose of LMWH was 0.95;95%Cl:0.42-2.13;P=0.9.The risk ratio of VTE after thromboprophylaxis with LMWH and unfractionated heparin(UFH)was 0.47;95%Cl:0.09-2.49;P=0.38.The risk of bleeding for thromboprophylaxis whit LMWH and Placebo was 12.7%and 9.7%,respectively.RR=1.38;95%Cl:1.17-1.62;P<0.0001;The risk ratio of major bleeding wasl.39;95%Cl:0.99-1.94;P=0.06;Relative risk of minor bleeding wasl.6;95%Cl:1.30-1.98;P<0.0001;The risk of postpartum hemorrhage were 8.8%and 12%,respectively,RR=1.10;95%CI:0.82-1.47;P=0.54.The bleeding risk of prophylactic and therapeutic doses of LMWH was 10.7%and 12.8%,RR=1.06;95%Cl:0.81-1.39;P=0.68.The major bleeding risk of thromboprophylaxis with LMWHor UFH were 0.5%and 2.2%respectively.The bone density of femur and vertebral has no significant decrease after application of LMWH during pregnancy,MD-0.02;95%CI:-0.05-0.01 P = 0.23 and MD-0.17;95%Cl:-0.43-0.08;P = 0.18.The heparin-induced thrombocytopenia risk of LMWH for thromboprophylaxis during pregnancy was 0.9%,the incidence of heparin-induced thrombocytopenia of UFH was 2.7%,RR=0.37;95%Cl:0.04-3.41;P=0.38.The risk of allergic skin lesion with LMWH during pregnancy was 0.4%,the incidence of allergic reactions with placebo was 0.1%,RR = 3.73;95%Cl:1.55-8.98;P=0.003.Conclusions:Prophylactic doses of LMWH is effective for preventing pregnancy-associated VTE in high risk group during pregnancy and postpartum.The use of prophylactic doses of LMWH does not increase major bleeding and postpartum hemorrhage(8.8%)but significantly increased the risk of minor bleeding(12.4%).The incidence of osteoporosis or fraction.heparin-induced thrombocytopenia and allergic skin lesion are acceptable with Long-term use of prophylactic doses of LMWH during pregnancy and puerperium.LMWH is effective and safe for preventing pregnancy-related VTE in high risk groups.There is insufficient evidence to prove that LMWH is superior to UFH in the efficacy and safety of preventing pregnancy-associated venous thromboembolism. |
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