单绒毛膜双胎选择性胎儿生长受限产妇胎盘血管铸型模型的建立及其形态学研究

摘要

目的 建立单绒毛膜双胎合并选择性宫内生长受限(sIUGR)胎盘血管铸型模型,并探讨其胎盘血管形态学改变及临床意义.方法 随机选取住院以剖宫产方式分娩且明确绒毛膜性质、孕周相同的单绒毛膜双羊膜囊双胎产妇20例,其中单绒毛膜双羊膜囊双胎合并sIUGR产妇10例(A组),再根据新生儿出生体重分为A1(大胎儿)组和A2(小胎儿)组;正常单绒毛膜双羊膜囊双胎组(无合并症、并发症)产妇10例(B组),再根据新生儿出生体重分为B1(大胎儿)组和B2(小胎儿)组.应用胎盘血管铸型的方法对两组产妇胎盘进行血管铸型并观测相关指标:(1)胎盘份额比值(大胎盘与小胎盘面积比);(2)标本铸型后,计量血管吻合支情况以及胎盘各级动、静脉的血管管腔内直径等指标;(3)比较A组与B组产妇胎盘血管形态学差异.结果 (1)两组产妇一般情况比较:A组产妇平均年龄(28.36 ±4.79)岁,平均分娩孕周(35.10±2.69)周;B组产妇平均年龄(31.04±5.13)岁,平均分娩孕周(35.32±2.66)周;A组两胎盘份额比值＞1.5,显著高于B组两胎盘份额比值.A组中有6例发生脐带的异常附着(球拍状或帆状胎盘);B组中只有1例发生脐带的异常附着(球拍状胎盘).(2)A组两胎儿胎盘间存在丰富的血管吻合支,两胎儿各级动静脉分级血管管内直径存在显著性差异.(3)B组两胎儿胎盘间血管吻合情况较A组明显减少,两胎儿各级动静脉分级血管管内直径数值差异较小.结论 (1)本研究通过对胎盘血管的铸型,观测及分析了相关形态学改变,验证了胎盘血管吻合、胎盘份额差异以及脐带插入方式对单绒毛膜双胎胎儿生长发育的影响;即胎盘份额差异越大、胎盘血管吻合及脐带的异常插入越常见,则新生儿出生体重差异就越大;(2)单绒毛膜双胎sIUGR产妇两胎盘血管容量、分级血管管内径、末梢动、静脉比值上存在显著性差异,这亦可能是单绒毛膜sIUGR的可能病因之一;(3)通过对单绒毛膜双胎胎盘血管铸型模型的建立,有助于提高对单绒毛膜双胎合并sIUGR的发病机制和临床表现的认识,对改善围产期结局也有重大意义.%Objective To establish the placental vascular cast model of monochorionic (MC) twin pregnancy with selected growth restrain,and to investigate the morphological changes of placental vascular and its clinical significance.Methods Twenty specimens were collected from women who delivery in Nanfang hospital of Southern Medical University with MC twin pregnancy,among whom 10 subjects with SIUGR were enrolled as Group A and 10 subjects with normal infants were enrolled as Group B.According to the birth weight,they were further subdivided into Group A1,Group A2,Group B1 and Group B2.The placental vascular cast models were constructed for comparison.Results The age in Group A ranged from 20 to 37,with the mean age of (28.36-± 4.79) years,and gestational week of (35.10 ± 2.69) weeks.The age in Group B ranged from 23 to 38,with mean age of (31.04-±5.13) years,gestational week of (35.32-± 2.66) weeks.In Group A,the share rate of two placenta was over 1.5,which was significantly higher than that in Group B.In Group A,6 cases of abnormal umbilical cord attachment (the racket shape or sail the placenta) were observed;as only 1 case of abnormal umbilical cord attachment was observed in Group B.In Group A,rich vascular anastomosis branches were revealed between the twin fetal placenta.There were significant differences in vascular diameters among veins and arteries.In Group B,the vascular anastomosis branches were significantly less than that in Group A,with significantly less diameter differences among vessels.Conclusion Placental vascular anastomosis,placenta sharing degree and abnormal umbilical cord attachment are proved to affect the growth of MC twin fetus.