Pelle G Lindqvist，  Karin Rova，  Henrik Passmark  瑞典Karolinska大学医院

　　体外受精妊娠（IVF）早期，静脉血栓栓塞（VTE）风险增加，合并卵巢过度刺激综合征（OHSS）风险也增加。3%??8%的IVF合并中或重度OHSS。促排卵后，使用人绒毛膜促性腺激素（hCG）诱导排卵或妊娠中内生hCG都与OHSS相关。IVF相关VTE多发生在上肢和颈部。据报道，VTE发生于胚胎植入（ET）后第40～42天。我们旨在确定IVF相关VTE的发生率和增加风险，以及成功受精周期中OHSS。

　　我们发现，IVF后VTE发生率0.2%，合并OHSS的新鲜IVF后VTE发生率1.7%，接近背景人群100倍。IVF早期VTE平均发生在孕龄62天（或ET后44～46天）。IVF相关OHSS比例不变（6%～7%）。冷冻胚胎移植（FER）周期并未增加风险。分娩前VTE总体发生率1.0/1000。高于1990??1999年瑞典数据（0.64/1000）。新生儿结局的差异主要存在于单胎和多胎妊娠，而非IVF妊娠和背景人群之间。

　　瑞典血栓预防指南推荐，分娩前（9个月）风险高于5%（如有过1次既往VTE病史）的女性使用低分子量肝素。但我们发现，早期妊娠合并OHSS的VTE风险1.7%，血栓预防治疗应延长至第13孕周。这一推荐将被纳入下版瑞典国家指南。

　　In-vitro fertilization (IVF) pregnancies are at an increased risk of VTE in early pregnancy and cases complicated by ovarian hyperstimulation syndrome (OHSS) are also at an increased risk. 3%～8% of IVF cycles are complicated by moderate or severe OHSS. The administration of hCG to induce ovulation or endogenous hCG are involved in the development of OHSS. IVF related VTE have the unusual propensity to be located in the upper extremities and the neck. These VTEs are reported to occur 40～42 days following embryo transfer (ET). We aimed to determine the incidence and increase in risk of VTE in relation to IVF and OHSS in successful  IVF cycles.

　　Our findings show the incidence of VTE after IVF treatment to be 0.2% and after fresh IVF complicated by OHSS 1.7%， a close to 100-fold increase as compared to the background population. VTEs during IVF treatment in the first trimester occurred at a gestational age of 62 days (or 44～46 days after ET). The proportion of IVF related OHSS is constant (6%～7%). FER cycles did not show an increased risk.

　　The total incidence of antepartum VTE was 1.0/1000， which is higher than the Swedish data from 1990～1999 (0.64/1000). The large differences in newborn outcomes are between singleton and multiple pregnancies， rather than between IVF pregnancies and the background population.

　　Swedish thromboprophylaxis guidelines are based on a recommendation that low molecular weight heparin is prescribed to women with a 5% antepartum (9 months) risk or higher， the antepartum risk of women with one prior VTE. Based on our findings， the 1.7% VTE risk in first trimester complicated by OHSS motivates that thromboprophylaxis should be extended until the 13th week of gestation. This is included in the next edition of the Swedish national guidelines.

　　延伸阅读

　　静脉血栓栓塞急性期治疗--ACCP 9指南解读

　　孙艺红    北京大学人民医院

　　与ACCP 8相比，ACCP 9基于证据等级良好的大规模临床研究，低分子量肝素（LMWH）和磺达肝癸钠为首选抗凝药物，而普通肝素地位下降。此外，ACCP 9更重视出血评估。

　　未能明确诊断的静脉血栓栓塞（VTE），临床高度可疑患者推荐抗凝治疗；临床中度可疑患者，如4小时内不能明确诊断，应立即抗凝；临床可疑度较低患者，如24小时内可确诊，不必马上抗凝（2级，C类）。

　　VTE急性期治疗推荐静脉抗凝药物与华法林合用，静脉抗凝药物包括：LMWH、磺达肝癸钠、普通肝素静脉或皮下注射。首选LMWH或磺达肝癸钠（1级，B类）。但需根据肾功能选择恰当剂量。LMWH剂量首选每日1次（2级，C类），临床研究证实给药每日1次不劣于每日2次。急性VTE治疗以LMWH联合维生素K拮抗剂（VKA）为主，之后过渡到华法林长期治疗。但肿瘤患者长期治疗推荐首选LMWH（2级，B类）。

　　对孤立远端深静脉血栓形成患者，如症状严重或存在血栓扩展危险因素，应开始抗凝治疗（1级，B类）。影像学评估监测2周，如发现血栓扩展，开始抗凝（1级，B类）。