title: Prevalences and pregnancy outcome of vanishing twin pregnancies achieved by in vitro fertilization versus natural conception.
abstract: OBJECTIVE
  To evaluate whether vanishing twin (VT) pregnancies achieved by in vitro fertilization and intracytoplasmic sperm injection (IVF-ICSI) had a more adverse perinatal outcome than those after natural conception.
  
  
  METHODS
  Longitudinal, retrospective cohort study.
  
  
  METHODS
  Tertiary university hospital.
  
  
  METHODS
  Three hundred and six (78 after IVF-ICSI and 228 after natural conception) VT pregnancies over a 22-year period, with VT cases matched to primarily singleton controls.
  
  
  METHODS
  None.
  
  
  METHODS
  Obstetric and neonatal outcome data.
  
  
  RESULTS
  The incidence of VT was statistically significantly higher after natural conception (18.2% of twins) than after IVF-ICSI (12.6% of twins). The odds of VT in pregnancies complicated with pregestational or gestational diabetes were disproportionally higher in IVF-ICSI cases than in spontaneously conceived VT pregnancies (adjusted odds ratio [AOR]: 0.80 vs. 3.10 and 1.00 vs. 1.07, respectively). Previous induced abortion (AOR 1.34) or second-trimester fetal loss (AOR 3.3) increased the risk of VT pregnancies after spontaneous conception. Gestational diabetes mellitus in both the previous (AOR 5.41) and the present (AOR 2.3) pregnancy as well as chronic maternal diseases (AOR 3.5) and placentation anomalies all represented independent risk factors for VT after IVF-ICSI.
  
  
  CONCLUSIONS
  Vanishing twin pregnancies had a lower prevalence and a worse perinatal outcome after IVF-ICSI as compared with those of their spontaneously conceived counterparts.
authors: Department of Obstetrics and Gynecology, University of Szeged, Szeged, Hungary. Electronic address: martonvirag@gmail.com.
authors: Virág
authors: V
authors: Márton
authors: Center for Assisted Reproduction, Kaáli Institute, University of Szeged, Szeged, Hungary.
authors: János
authors: J
authors: Zádori
authors: Department of Obstetrics and Gynecology, Blekinge Hospital, Karlskrona, Sweden.
authors: Zoltan
authors: Z
authors: Kozinszky
authors: Department of Obstetrics and Gynecology, University of Szeged, Szeged, Hungary.
authors: Attila
authors: A
authors: Keresztúri
mesh_terms: D000022:Abortion, Spontaneous / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D000328:Adult; D016009:Chi-Square Distribution; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro / Q000009:adverse effects*; D006785:Hospitals, University; D006801:Humans; D006814:Hungary / Q000453:epidemiology; D015994:Incidence; D007246:Infertility / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy*; D016015:Logistic Models; D008137:Longitudinal Studies; D015999:Multivariate Analysis; D016017:Odds Ratio; D011247:Pregnancy; D059285:Pregnancy, Twin; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D020554:Sperm Injections, Intracytoplasmic / Q000009:adverse effects; D013997:Time Factors; D016896:Treatment Outcome
keywords: IVF–ICSI; natural conception; perinatal outcome; singleton pregnancy; vanishing twin