title: Monochorionic diamniotic in vitro fertilization twins have a decreased incidence of twin-to-twin transfusion syndrome.
abstract: OBJECTIVE
  To compare the incidence of twin-to-twin transfusion syndrome (TTTS) in spontaneous versus IVF-conceived twin pregnancies.
  
  
  METHODS
  Retrospective multicenter study.
  
  
  METHODS
  University-affiliated tertiary medical centers.
  
  
  METHODS
  Women admitted for 11-14 week's scan between January 1997 and July 2013 who were diagnosed with monochorionic (MC) diamniotic twin pregnancies.
  
  
  METHODS
  None.
  
  
  METHODS
  Mode of conception, TTTS.
  
  
  RESULTS
  The study cohort included 327 pregnant women with live MC diamniotic twins. Of them, 284 (86.9%) and 43 (13.1%) were spontaneous and IVF conceived, respectively. The mean maternal age was significantly higher in IVF compared with in spontaneously conceived pregnancies (33.8 ± 5.5 vs. 31.6 ± 5.4, respectively). Thirty-seven twins (11.3%) had TTTS, of whom 36/284 (12.7%) versus 1/43 (2.3%) were spontaneously and IVF conceived, respectively. The mean week of delivery was significantly lower in MC twins diagnosed with TTTS compared with those without TTTS (32.7 ± 3.3 vs. 35.5 ± 2.5, respectively). Furthermore, there was a significantly higher birthweight discordancy in twins diagnosed with TTTS compared with those without (20.6% vs. 11%, respectively).
  
  
  CONCLUSIONS
  The significantly lower proportion of TTTS found in IVF-conceived twins may suggest a different embryological process that lies at the core of IVF conception of monozygotic twinning.
authors.affiliation: Department of Obstetrics and Gynecology, Assaf Harofeh Medical Center, Zerifin, Israel.
authors.forename: Ido
authors.initials: I
authors.lastname: Ben-Ami
authors.affiliation: Maternal-Fetal Medicine Unit, Department of Obstetrics and Gynaecology, University Hospital, Granada, Spain.
authors.forename: Francisca Sonia
authors.initials: FS
authors.lastname: Molina
authors.affiliation: Women's Health Center Clalit Afula, Israel.
authors.forename: Shlomo
authors.initials: S
authors.lastname: Battino
authors.affiliation: Department of Obstetrics and Gynecology, Emek Medical Center, Afula, Israel, Rappaport Faculty of Medicine, Technion -Israel Institute of Technology, Haifa, Israel.
authors.forename: Etty
authors.initials: E
authors.lastname: Daniel-Spiegel
authors.affiliation: Department of Obstetrics and Gynecology, Assaf Harofeh Medical Center, Zerifin, Israel.
authors.forename: Yaakov
authors.initials: Y
authors.lastname: Melcer
authors.affiliation: Department of Obstetrics and Prenatal Medicine, University Medical School, Bonn, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Flöck
authors.affiliation: Department of Obstetrics and Prenatal Medicine, University Medical School, Bonn, Germany.
authors.forename: Annegret
authors.initials: A
authors.lastname: Geipel
authors.affiliation: Galilee Medical Centre, Nahariya and Galilee Faculty of Medicine, Safed, Israel.
authors.forename: Marwan
authors.initials: M
authors.lastname: Odeh
authors.affiliation: Centre de Procreation FERTILYS, Laval, Quebec, Canada.
authors.forename: Pierre
authors.initials: P
authors.lastname: Miron
authors.affiliation: Department of Obstetrics and Gynecology, Assaf Harofeh Medical Center, Zerifin, Israel. Electronic address: maymonrb@bezeqint.net.
authors.forename: Ron
authors.initials: R
authors.lastname: Maymon
mesh_terms: D000328:Adult; D001724:Birth Weight; D004624:Embryo Transfer; D005260:Female; D005298:Fertility; D005307:Fertilization in Vitro / Q000009:adverse effects; D005330:Fetofetal Transfusion / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D005865:Gestational Age; D006801:Humans; D015994:Incidence; D007246:Infertility / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D050498:Live Birth; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D059285:Pregnancy, Twin; D012189:Retrospective Studies; D016896:Treatment Outcome; D014430:Twins, Monozygotic
keywords: IVF; TTTS; incidence; monozygosity; twins