title: Correlation between cord insertion type and chorionic villus vascularization of the co-twin in diamniotic-monochorionic twin pregnancies.
abstract: BACKGROUND
  Recent evidence suggests that cord insertion type of one twin correlates with chorionic plate vascularization of the monochorionic co-twin. Specifically, for twins with paracentral cords, chorionic plate vascularization is significantly greater when the co-twin has a velamentous, rather than paracentral cord insertion.
  
  
  OBJECTIVE
  To determine whether this correlation between cord insertion type and vascularization of the co-twin also extends to the deeper chorionic villus tree.
  
  
  METHODS
  Morphometric analysis of chorionic villus vascularization in CD31-immunostained sections of a retrospective cohort of gestational age-matched third trimester monochorionic placentas with discordant paracentral/velamentous (PC/V) or concordant paracentral/paracentral (PC/PC) cord insertions.
  
  
  METHODS
  Vascular numerical density (number of vascular profiles per unit villus stromal area) of intermediate villi (>80 μm diameter) and terminal villi (<80 μm).
  
  
  RESULTS
  For twins with paracentral cord insertion, the vascular numerical density of intermediate villi was significantly higher for twins in a discordant PC/V relationship than for those in a concordant PC/PC relationship (P<0.05), thus replicating previous findings in superficial chorionic vessels. For terminal villi, in contrast, the vascular numerical density of twins with paracentral cords in a PC/V combination was significantly lower than of those in a PC/PC combination, and similar to that of their co-twins with velamentous cord insertion.
  
  
  CONCLUSIONS
  Early placental angiogenesis in monochorionic twin gestations may be influenced by implantation and cord localization of the co-twin. The regulation of terminal villus angiogenesis appears to be dissociated from more proximal villus angiogenesis and independent of cord insertion of the co-twin.
authors: Department of Pathology, Women and Infants Hospital, Alpert Medical School of Brown University, Providence, RI 02905, USA.
authors: Sharon
authors: S
authors: Chu
authors: Quanfu
authors: Q
authors: Mao
authors: Svetlana
authors: S
authors: Shapiro
authors: Sophie L
authors: SL
authors: Luks
authors: Monique E
authors: ME
authors: De Paepe
mesh_terms: D000328:Adult; D000650:Amnion / Q000033:anatomy & histology; D002824:Chorionic Villi / Q000098:blood supply*; D005260:Female; D006801:Humans; D018919:Neovascularization, Physiologic; D011247:Pregnancy; D059285:Pregnancy, Twin; D014470:Umbilical Cord / Q000033:anatomy & histology*