摘要目的 通过对单绒毛膜双胎胎盘浅表吻合血管、胎盘份额、脐带附着位置的比较,探讨双胎输血综合征胎盘(TTTS)结构的特点.方法 收集2013年6月至2014年6月于北京大学第三医院终止妊娠后确定的单绒毛膜双胎共97例,剔除分娩后胎盘破损或孕期行胎儿镜激光治疗的胎盘18例,共取得79例孕期未行胎儿镜激光治疗且分娩后完整保存的胎盘,对该79例胎盘行浅表血管灌注.剔除选择性官内生长受限(sIUGR)胎盘23例,对TTTS胎盘24例和无并发症单绒毛膜双胎(未发生TTTS、sIUGR等复杂性双胎妊娠)胎盘32例进行比较研究.结果 (1)TTTS组胎盘A-A吻合血管发生率较无并发症组显著降低(37.5％比75.0％,P＜0.01),差异有统计学意义.两组之间A-V吻合血管发生率(87.5％比71.9％,P＞0.05)、V-V吻合血管发生率(20.8％比15.6％,P＞0.05)差异无统计学意义.(2)A-A吻合血管数目在TTTS组明显少于无并发症组(0.0比1.0,P＜0.01),A-A吻合血管直径总和在TTTS组明显低于无并发症组(0.00 mm比2.25 mm,P＜0.01),差异均有统计学意义.(3)两组之间脐带非中央附着发生率(70.8％比62.5％,P＞0.05)、脐带帆状附着(25.0％比6.3％,P ＞0.05)及胎盘面积差额比(0.33比0.22,P＞0.05),差异无统计学意义.结论 动脉—动脉吻合血管可能是单绒毛膜双胎免于TTTS的保护因素,缺少动脉—动脉吻合血管的单绒毛膜双胎,孕期发生TTTS风险明显增高.不同胎盘动脉—动脉吻合血管的代偿能力可能决定了TTTS发病的时间早晚.胎盘分割不均、脐带非中央附着和帆状附着都不是TTTS发病的危险因素.

abstractsObjective To explore the prevalence,number and size of anastomoses,placenta sharing and placental cord insertion in twin-to-twin transfusion syndrome (TTTS).Methods A total of 97 monochorionic placentas were collected from June 2013 to June 2014 during fetoscopic laser surgery or selective feticide.After eliminating 23 placentas of selective intrauterine growth restriction (sIUGR),79 placents were analyzed.There were 24 placentas of TTTS and 32 placentas of normal monochorionic twins (McT) without complex twin preganancy.Placental sharing,placental cord insertion,angioarchitecture and diameter of vascular anastomosis were assessed by placental injection with colored dye and compared between TTTS and McT without complex twin preganancy.Results (1) Arterio-arterial (AA) anastomoses were detected in 37.5 ％ of TTTS placentas versus 75.0％ in normal McT placentas (P ＜ 0.01).(2) The median number of AA anastomoses in TTTS group was significantly less than that in normal group (0.0 vs 1.0,P ＜ 0.01).And the median total diameter of AA anastomoses in TTTS group was significantly smaller than that in normal group (0.00 vs 2.25 mm,P ＜0.01).(3) The incidence of placentas with at least one cord noncentral insertion (70.8 ％ vs 62.5 ％,P ＞ 0.05),velamentous insertion (25.0％ vs 6.3 ％,P ＞ 0.05) in TTTS and normal McT had no difference respectively.The placental territory discordance (PTD) had no difference between TTTS and normal McT (0.33 vs 0.22,P ＞0.05).Conclusion AA anastomosis occurs less frequently in TTTS placentas,supporting the concept of a protective role of AA anastomoses in TTTS.McT placentas without AA anastomosis have high risk for TTTS.The compensatory ablitiy of AA anastomosis may determine the time of TTTS onset.Non-central or velamentous cord insertion,placental sharing discordance are not risk factors for TTTS.