title: 'Superficial' anastomoses in monochorionic placentas are not always superficial.
abstract: Arterioarterial (AA) and venovenous (VV) anastomoses in monochorionic (MC) placentas lie on the placental surface and are termed as superficial anastomoses. The purpose of this study is to report the occurrence of an atypical form of superficial anastomoses which are partially hidden. Partially-hidden superficial anastomoses were defined as vascular anastomoses without visible direct connection on placental surface but with clear mixing of dye after colored dye injection. With analyzing 270 MC placentas, we found a prevalence of partially-hidden AA and VV anastomose of 3% and 5%, respectively. In conclusion, partially-hidden superficial anastomose are not infrequent in MC placentas.
authors.affiliation: Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: d.zhao@lumc.nl.
authors.forename: D P
authors.initials: DP
authors.lastname: Zhao
authors.affiliation: Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Q
authors.initials: Q
authors.lastname: Dang
authors.affiliation: Division of Fetal Medicine, Department of Obstetrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: M C
authors.initials: MC
authors.lastname: Haak
authors.affiliation: Division of Fetal Medicine, Department of Obstetrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: J M
authors.initials: JM
authors.lastname: Middeldorp
authors.affiliation: Division of Fetal Medicine, Department of Obstetrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: F J C M
authors.initials: FJ
authors.lastname: Klumper
authors.affiliation: Division of Fetal Medicine, Department of Obstetrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: D
authors.initials: D
authors.lastname: Oepkes
authors.affiliation: Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Lopriore
mesh_terms: D001159:Arterio-Arterial Fistula / Q000473:pathology; D005260:Female; D006801:Humans; D010920:Placenta / Q000098:blood supply* / Q000473:pathology; D011247:Pregnancy; D059285:Pregnancy, Twin; D014430:Twins, Monozygotic
keywords: Arterioarterial anastomoses; Monochorionic placenta; Venovenous anastomoses