title: Short- and long-term perinatal outcome in twin pregnancies affected by weight discordance.
abstract: BACKGROUND
  The objective was to investigate the association between chorionicity-specific intertwin birthweight discordance and adverse outcomes including long-term follow up at 6, 18, and 48-60 months after term via Ages and Stages Questionnaire.
  
  
  METHODS
  In this secondary analysis of a cohort study (Oldenburg et al., n = 1688) and a randomized controlled trial (PREDICT study, n = 1045) twin pairs were divided into three groups according to chorionicity-specific birthweight discordance: <75th percentile, 75th-90th percentile and >90th percentile. Information on infant mortality, admittance to neonatal intensive care units, and gestational age at delivery was available for all pairs. Detailed neonatal outcomes were available for 656 pairs from PREDICT, of which 567 pairs had at least one Ages and Stages Questionnair follow-up. Logistic regression models were used for dichotomous outcomes. Ages and Stages Questionnair scores were compared using the method of generalized estimating equation to account for the correlation within twins.
  
  
  RESULTS
  The 75th and 90th percentiles for birthweight discordance were 14.8 and 21.4% for monochorionic and 16.0 and 23.8% for dichorionic twins. After adjustment for small for gestational age and gender, birthweight discordance >75th and >90th percentile was associated with induced delivery <34 weeks [odds ratio 1.71 (95% confidence interval 1.11-2.65) and odds ratio 2.83 (95% confidence interval 1.73-4.64), respectively]. Discordance >75th-percentile was associated with an increased risk of infant mortality after 28 days [odds ratio 4.69 (95% confidence interval 1.07-20.45)] but not with major neonatal complications or with low mean Ages and Stages Questionnair scores at 6, 18, and 48-60 months after term.
  
  
  CONCLUSIONS
  Chorionicity-specific intertwin birthweight discordance is a risk factor for induced preterm delivery and infant mortality, but not for lower scores for neurophysiological development at 6, 18, and 48-60 months.
authors.affiliation: Center of Fetal Medicine and Pregnancy, Department of Obstetrics, Rigshospitalet University Hospital, Copenhagen, Denmark.
authors.forename: Cathrine
authors.identifier: http://orcid.org/0000-0001-7475-513X
authors.initials: C
authors.lastname: Vedel
authors.affiliation: Center of Fetal Medicine and Pregnancy, Department of Obstetrics, Rigshospitalet University Hospital, Copenhagen, Denmark.
authors.forename: Anna
authors.initials: A
authors.lastname: Oldenburg
authors.affiliation: Department of Obstetrics and Gynecology, Medical University of Vienna, Vienna, Austria.
authors.forename: Katharina
authors.initials: K
authors.lastname: Worda
authors.affiliation: Department of Obstetrics and Gynecology, Aalborg Hospital, Aalborg, Denmark.
authors.forename: Helle
authors.initials: H
authors.lastname: Larsen
authors.affiliation: Department of Obstetrics and Gynecology, Viborg Hospital, Viborg, Denmark.
authors.forename: Anni
authors.initials: A
authors.lastname: Holmskov
authors.affiliation: Department of Obstetrics and Gynecology, Hvidovre Hospital, Hvidovre, Denmark.
authors.forename: Kirsten R
authors.initials: KR
authors.lastname: Andreasen
authors.affiliation: Department of Obstetrics and Gynecology, Aarhus University Hospital, Skejby, Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Uldbjerg
authors.affiliation: Department of Obstetrics and Gynecology, Sønderborg Hospital, Sønderborg, Denmark.
authors.forename: Jan
authors.initials: J
authors.lastname: Ramb
authors.affiliation: Department of Obstetrics and Gynecology, Nordsjaellands Hospital, Hillerød, Denmark.
authors.forename: Birgit
authors.initials: B
authors.lastname: Bødker
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital Roskilde, Roskilde, Denmark.|Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Lillian
authors.initials: L
authors.lastname: Skibsted
authors.affiliation: Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.|Department of Obstetrics and Gynecology, Herlev Hospital, Herlev, Denmark.
authors.forename: Lene
authors.initials: L
authors.lastname: Sperling
authors.affiliation: Department of Obstetrics and Gynecology, Klagenfurt General Hospital, Klagenfurt, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Hinterberger
authors.affiliation: Department of Obstetrics and Gynecology, Holbaek Hospital, Holbaek, Denmark.
authors.forename: Lone
authors.identifier: http://orcid.org/0000-0001-5433-4776
authors.initials: L
authors.lastname: Krebs
authors.affiliation: Department of Obstetrics and Gynecology, Glostrup Hospital, Glostrup, Denmark.
authors.forename: Helle
authors.initials: H
authors.lastname: Zingenberg
authors.affiliation: Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Denmark.
authors.forename: Eva-Christine
authors.initials: EC
authors.lastname: Weiss
authors.affiliation: Department of Obstetrics and Gynecology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Isolde
authors.initials: I
authors.lastname: Strobl
authors.affiliation: Department of Obstetrics and Gynecology, Odense University Hospital, Odense, Denmark.
authors.forename: Lone
authors.initials: L
authors.lastname: Laursen
authors.affiliation: Department of Obstetrics and Gynecology, Gentofte Hospital, Gentofte, Denmark.
authors.forename: Jeanette T
authors.initials: JT
authors.lastname: Christensen
authors.affiliation: Department of Obstetrics and Gynecology, Silkeborg Hospital, Silkeborg, Denmark.
authors.forename: Vibeke
authors.initials: V
authors.lastname: Ersbak
authors.affiliation: Department of Obstetrics and Gynecology, Randers Hospital, Randers, Denmark.
authors.forename: Inger
authors.initials: I
authors.lastname: Stornes
authors.affiliation: Department of Obstetrics and Gynecology, Medical University of Vienna, Vienna, Austria.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Krampl-Bettelheim
authors.affiliation: Center of Fetal Medicine and Pregnancy, Department of Obstetrics, Rigshospitalet University Hospital, Copenhagen, Denmark.|Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Ann
authors.initials: A
authors.lastname: Tabor
authors.affiliation: Center of Fetal Medicine and Pregnancy, Department of Obstetrics, Rigshospitalet University Hospital, Copenhagen, Denmark.
authors.forename: Line
authors.initials: L
authors.lastname: Rode
mesh_terms: D001724:Birth Weight; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases; D007236:Infant, Small for Gestational Age; D007363:Intensive Care Units, Neonatal; D007751:Labor, Induced; D010343:Patient Admission; D011247:Pregnancy; D059285:Pregnancy, Twin; D047928:Premature Birth; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects
keywords: Ages and Stages Questionnaire; Chorionicity; birthweight discordance; neonatal complications; twins