title: Placental cord insertion and birthweight discordance in twin pregnancies: results of the national prospective ESPRiT Study.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the impact of noncentral placental cord insertion on birthweight discordance in twins.
  
  
  METHODS
  We performed a multicenter, prospective trial of twin pregnancies. Placental cord insertion was documented as central, marginal, or velamentous according to a defined protocol. Association of the placental cord insertion site with chorionicity, birthweight discordance, and growth restriction were assessed.
  
  
  RESULTS
  Eight hundred sixteen twin pairs were evaluated; 165 pairs were monochorionic, and 651 pairs were dichorionic. Monochorionic twins had higher rates of marginal (P = .0068) and velamentous (P < .0001) placental cord insertion. Noncentral placental cord insertion was more frequent in smaller twins of discordant pairs than control pairs (29.8% vs 19.1%; P = .004). Velamentous placental cord insertion in monochorionic twins was associated significantly with birthweight discordance (odds ratio, 3.5; 95% confidence interval, 1.3-9.4) and growth restriction (odds ratio, 4; 95% confidence interval, 1.1-14.3).
  
  
  CONCLUSIONS
  Noncentral placental cord insertion contributes to birthweight discordance in monochorionic twin pregnancies. Sonographic delineation of placental cord insertion may be of value in antenatal assessment of twin pregnancies.
authors.affiliation: Royal College of Surgeons in Ireland, Dublin, Ireland. ekent@rcsi.ie
authors.forename: Etaoin M
authors.initials: EM
authors.lastname: Kent
authors.forename: Fionnuala M
authors.initials: FM
authors.lastname: Breathnach
authors.forename: John E
authors.initials: JE
authors.lastname: Gillan
authors.forename: Fionnuala M
authors.initials: FM
authors.lastname: McAuliffe
authors.forename: Michael P
authors.initials: MP
authors.lastname: Geary
authors.forename: Sean
authors.initials: S
authors.lastname: Daly
authors.forename: John R
authors.initials: JR
authors.lastname: Higgins
authors.forename: James
authors.initials: J
authors.lastname: Dornan
authors.forename: John J
authors.initials: JJ
authors.lastname: Morrison
authors.forename: Gerard
authors.initials: G
authors.lastname: Burke
authors.forename: Shane
authors.initials: S
authors.lastname: Higgins
authors.forename: Stephen
authors.initials: S
authors.lastname: Carroll
authors.forename: Patrick
authors.initials: P
authors.lastname: Dicker
authors.forename: Fiona
authors.initials: F
authors.lastname: Manning
authors.forename: Fergal D
authors.initials: FD
authors.lastname: Malone
mesh_terms: D001724:Birth Weight; D005260:Female; D006801:Humans; D010920:Placenta / Q000033:anatomy & histology*; D011247:Pregnancy; D011446:Prospective Studies; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic; D014470:Umbilical Cord / Q000033:anatomy & histology*