title: Cyclic changes in the umbilical arterial flow in mono-chorionic, di-amniotic twin pregnancy.
abstract: OBJECTIVE
  To determine the effect of arterio-arterial anastomosis on the umbilical arterial flow in mono-chorionic, di-amniotic twin pregnancy.
  
  
  METHODS
  Thirty-three women with mono-chorionic, di-amniotic twin pregnancy.
  
  
  METHODS
  Pulsed Doppler ultrasonographic examination was performed every 4 weeks to obtain umbilical arterial flow velocity waveforms in both two fetuses.
  
  
  RESULTS
  In five of the women, cyclic flow changes in the umbilical arterial flow were detected in the smaller fetus. All of these twins had arterio-arterial anastomosis on the surface of the placenta.
  
  
  CONCLUSIONS
  The fetuses in mono-chorionic and di-amniotic twin gestation who showed cyclic changes in umbilical arterial flow had arterio-arterial anastomosis. But, this characteristic flow was not observed every time.
authors.affiliation: Department of Obstetrics and Gynecology, Medical School, Osaka City University, 1-4-3 Asaci-Machi, Abeno, 545-8585, Osaka, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Nakai
authors.forename: Osamu
authors.initials: O
authors.lastname: Ishiko
authors.forename: Junko
authors.initials: J
authors.lastname: Nishio
authors.forename: Shin ichiro
authors.initials: Si
authors.lastname: Suzuki
authors.forename: Makiko
authors.initials: M
authors.lastname: Mine
authors.forename: Motoharu
authors.initials: M
authors.lastname: Imanaka
authors.forename: Sachio
authors.initials: S
authors.lastname: Ogita
mesh_terms: D001163:Arteriovenous Anastomosis / Q000000981:diagnostic imaging; D002823:Chorion / Q000098:blood supply*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D021041:Placental Circulation; D011247:Pregnancy; D012039:Regional Blood Flow; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic; D018617:Ultrasonography, Doppler, Pulsed; D014469:Umbilical Arteries / Q000000981:diagnostic imaging / Q000502:physiology*