摘要目的 探讨双胎输血综合征(TTTS)、双胎出生体质量不一致与单绒毛膜(MC)双胎胎盘血管分布的关系.方法 选取2010年2月至201 1年2月于北京大学第三医院流产及分娩的28例MC双胎胎盘进行血管灌注,对胎盘血管分布类型(分为平行型、交错型、混合型及单羊膜型)、吻合血管及胎盘分割比例等进行记录,分析MC双胎的妊娠结局,观察非TTTS双胎活产出生体质量不一致者(出生体质量差≥20％)的胎盘血管分布的特点.结果 (1)妊娠结局:28例MC双胎孕产妇流产或分娩孕周为20 ～ 38周(中位数为孕35周),其中TTTS6例,3例行胎儿镜激光凝固阻断吻合血管术(FLOC).共有活产儿48个,平均出生体质量(2036±623)g.(2)胎盘血管分布类型:28例MC双胎中胎盘血管分布类型为平行型4例(14％),交错型14例(50％),混合型6例(21％),另有4例(14％)以单羊膜型分布.TTTS胎盘血管分布类型中无平行型.不同类型吻合血管在平行型、交错型及混合型胎盘血管分布类型中分别比较,差异均无统计学意义(P＞0.05)；胎盘分割不均分别为4例(4/4)、8例(8/14)及6例(6/6),分别比较,差异均无统计学意义(P＞0.05).(3)双胎出生体质量不一致的胎盘血管分布特点:非TTTS MC双胎活产产妇共20例,其中双胎儿出生体质量差≥20％(为出生体质量不一致)6例,双胎儿出生体质量差＜20％(为出生体质量一致)14例,两者胎盘分割不均的比例比较,差异有统计学意义(P＜0.01)；两者的脐带胎盘附着特点、胎盘血管分布类型、吻合血管类型及数目比较,差异均无统计学意义(P＞0.05).结论 双胎胎盘血管分布类型可能与TTTS有关；胎盘分割不均是非TTTS MC双胎出生体质量不一致的危险因素.

abstractsObjective To study the placental vascular distribution of monochorionic (MC) twins with twin-to-twin transfusion syndrome (TTTS) or hirth weight discordance.Methods Twenty-eight MC placentas were injected in Peking University Third Hospital between Feb.2010 and Feb.2011.The vascular distribution type (parallel,crossed,mixed and monoamniotic),the anastomosis of vessels and the placental sharing were recorded.The outcome of pregnancy and the placental characteristics of birth weight discordance (birth weight discordance ≥ 20％) in non-TTTS MC twins were analyzed.Results (1) The outcome of pregnancy:the miscarriage or gestational weeks of 28 MC twins were 20 to 38 weeks (median of 35 weeks).Six cases were TTTS,3 of which received fetoscopic laser occlusion of communicating vessels (FLOC).There were 48 live births,with an average birth weight of (2036 ± 623) g.(2) Type of placental vascular distribution:in the 28 MC placentas,number of parallel,crossed,mixed and monoamniotic type of placental vascular distribution were 4 (14％),14 (50％),6 (21％) and 4 (14％) cases,respectively.No parallel type was found in TTTS.There was no significant difference of vascular anastomosis or unequal placental sharing among the different placental vascular distribution types (P ＞ 0.05).(3) Characteristics of placental vascular distribution in birth weight discordance twins:there were 20 non-TTTS MC twin pregnancies,all of which got live births of both babies.Birth weight discordance equal to or more than 20％ was found in 6 pairs of newborns,while birth weight discordance less than 20％ was found in the rest 14 cases.Ratio of unequal placental sharing was significantly different between the two groups (P ＜ 0.01).There was no significant difference of umbilical cord insertion,placental vascular distribution and anastomosis in the two groups (P ＞0.01).Conclusions Vascular distribution type of MC twins might be related to TTTS.Unequal placental sharing is a risk factor of birth weight discordance in non-TTTS MC twins.