title: Perinatal outcomes after fresh versus vitrified-warmed blastocyst transfer: retrospective analysis.
abstract: OBJECTIVE
  To investigate the possible effect of controlled ovarian stimulation on the perinatal outcomes of assisted reproductive technology pregnancies, by comparing the outcomes from fresh ET with frozen ET (FET) with blastocysts of similar quality.
  
  
  METHODS
  Retrospective observational study.
  
  
  METHODS
  Private fertility center.
  
  
  METHODS
  Seven hundred eighty-four fresh transfers and 382 vitrified-warmed double blastocyst transfers.
  
  
  METHODS
  None.
  
  
  METHODS
  Miscarriage, perinatal mortality, preterm delivery, live birth, live-birth weights, and gestational age of live births.
  
  
  RESULTS
  FET resulted in higher implantation rates (51.5% vs. 40.6%), higher live-birth rates per transfer (56.8% vs. 44.3%), and lower ectopic pregnancy rates (0.32% vs. 1.80%). FET pregnancies also had higher day 14 βhCG levels per implantation (148.2 vs. 176.2 IU/L) and higher infant birth weights (singletons Δ109.4 g, twins Δ124 g). Female infants benefitted the most in terms of birth weight. Miscarriage, premature delivery, perinatal morbidity, and live birth per pregnancy were all nonsignificantly different between fresh ET and FET.
  
  
  CONCLUSIONS
  Clinically significant differences between the peri-implantation and perinatal outcomes of fresh ET and FET suggest better endometrial receptivity and placentation in FET cycles.
authors.affiliation: Antalya IVF, Özel Antalya Tüp Bebek Merkezi, Antalya, Turkey. Electronic address: kemalozg@yahoo.com.
authors.forename: Kemal
authors.initials: K
authors.lastname: Ozgur
authors.affiliation: Antalya IVF, Özel Antalya Tüp Bebek Merkezi, Antalya, Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Berkkanoglu
authors.affiliation: Antalya IVF, Özel Antalya Tüp Bebek Merkezi, Antalya, Turkey.
authors.forename: Hasan
authors.initials: H
authors.lastname: Bulut
authors.affiliation: The Fertility Clinic, Skive Regional Hospital and Faculty of Health, Aarhus University, Aarhus, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Humaidan
authors.affiliation: Antalya IVF, Özel Antalya Tüp Bebek Merkezi, Antalya, Turkey.
authors.forename: Kevin
authors.initials: K
authors.lastname: Coetzee
mesh_terms: D000022:Abortion, Spontaneous / Q000453:epidemiology; D000328:Adult; D001724:Birth Weight; D001755:Blastocyst; D015925:Cryopreservation; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D050498:Live Birth / Q000453:epidemiology; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D018873:Pregnancy Rate; D047928:Premature Birth / Q000453:epidemiology; D012189:Retrospective Studies; D058989:Vitrification
keywords: COS; HRT-FET; blastocysts; fresh ET; perinatal outcomes; pregnancy; vitrification