title: Velamentous cord insertion in dichorionic and monochorionic twin pregnancies - Does it make a difference?
abstract: To estimate the prevalence of velamentous cord insertion (VCI) in dichorionic (DC) and monochorionic (MC) twins with and without twin-twin transfusion syndrome (TTTS), and to study the associated outcomes.
  
  
  
  We recorded the type of umbilical cord insertion in all consecutive DC and MC placentas examined in two European tertiary medical centers. The association between VCI and perinatal outcomes was estimated and compared.
  
  
  
  A total of 1498 twin placentas were included in this study (DC placentas n = 550, MC placentas without TTTS n = 513 and MC placentas with TTTS n = 435). The prevalence of VCI in DC, MC without TTTS and MC with TTTS groups was 7.6%, 34.7% and 36.1%, respectively (P < 0.001). In MC twins (non-TTTS and TTTS groups), VCI was associated with severe birth weight discordance (odds ratio [OR] 4.76 95% CI 2.43, 10.47 and OR 4.52 95% CI 1.30, 28.59, respectively). In MC twins without TTTS, VCI was associated with small for gestational age (OR 1.66, 95% CI 1.12, 2.50). VCI was significantly associated with increased risk of intrauterine fetal demise in MC twins, and this effect was greater in the non-TTTS group (OR 2.71 95% CI 1.38, 5.47). These associations did not occur in DC group. Gestational age at birth was lower in the presence of VCI in the DC and MC twins without TTTS.
  
  
  
  Our findings confirm that the prevalence of VCI is higher in MC twins than in DC twin pregnancies. VCI is an important indicator of adverse perinatal outcome, particularly in MC twins.
authors.affiliation: Department of Obstetrics and Gynecology, São João Hospital Center, Medical Faculty University of Porto, Porto, Portugal. Electronic address: teresacostacastro@gmail.com.
authors.forename: T
authors.initials: T
authors.lastname: Costa-Castro
authors.affiliation: Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: D P
authors.initials: DP
authors.lastname: Zhao
authors.affiliation: 1st Department of Obstetrics and Gynecology of Medical University of Warsaw, Warsaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Lipa
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: D
authors.initials: D
authors.lastname: Oepkes
authors.affiliation: Epidemiology Unit, Medical Faculty University of Porto, Porto, Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Severo
authors.affiliation: Department of Obstetrics and Gynecology, São João Hospital Center, Medical Faculty University of Porto, Porto, Portugal.
authors.forename: N
authors.initials: N
authors.lastname: Montenegro
authors.affiliation: Department of Obstetrics and Gynecology, São João Hospital Center, Medical Faculty University of Porto, Porto, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Matias
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: D005260:Female; D005313:Fetal Death; D005330:Fetofetal Transfusion / Q000453:epidemiology* / Q000473:pathology; D005865:Gestational Age; D006801:Humans; D008297:Male; D010920:Placenta / Q000473:pathology*; D010922:Placenta Diseases / Q000453:epidemiology* / Q000473:pathology; D011247:Pregnancy; D059285:Pregnancy, Twin; D015995:Prevalence; D014470:Umbilical Cord / Q000473:pathology*
keywords: Dichorionic twins; Intrauterine fetal demise; Monochorionic twins; Severe birth weight discordance; Twin-twin transfusion syndrome; Velamentous cord insertion