title: Predictive factors of healthy term birth after single blastocyst transfer.
abstract: BACKGROUND
  Blastocyst culture and elective single embryo transfer programmes are increasingly used to reduce multiple pregnancies after IVF. To optimize the results, there is a need to better select embryos, to implement efficient cryopreservation programmes and to refine selection criteria. In the present study, we set out to identify relevant clinical predictors of healthy term birth (HTB) after single blastocyst transfer (SBT).
  
  
  METHODS
  
  
  
  METHODS
  analysis of prospectively collected database.
  
  
  METHODS
  University IVF centre in Nantes, France. In 872 infertile women undergoing their first IVF cycle with SBT between January 2007 and December 2008, multivariable analysis and logistic regression were used to identify predictive factors of HTB, i.e. delivery of a live born term singleton of ≥ 2500 g, surviving at least 28 days with no reported congenital anomaly.
  
  
  RESULTS
  Of 304 deliveries, there were 16 twin pairs (5.5%) and no high order deliveries. The rate of HTB was 266/872 (30.5%). Univariate analysis showed that the probability of HTB was significantly higher in women under 35 years [odds ratio (OR):1.75, 0.95 confidence interval (CI): 1.2-2.5, P = 0.001], in women with a BMI < 30 kg/m² (OR: 3.0, 0.95 CI: 1.5-5.9, P = 0.001), in non-smoking women (OR: 2.2, 0.95 CI: 1.5-3.2, P < 0.0001), and after Day 5 compared with after Day 6 transfer (OR: 2.65, 0.95 CI: 1.8-3.8, P < 0.0001). Multivariable analysis showed that BMI, smoking and day of embryo transfer were independent predictors of HTB, regardless of female age.
  
  
  CONCLUSIONS
  After SBT, female obesity and smoking reduce the chance of HTB, independent of female age. Day 6 transfer should be avoided.
authors.affiliation: CHU Nantes, service de médecine et biologie de la reproduction, Centre Hospitalier Universitaire de Nantes, 38, Bd Jean Monnet, 44093 Nantes Cedex 1, France. lionel.dessolle@yahoo.fr
authors.forename: Lionel
authors.initials: L
authors.lastname: Dessolle
authors.forename: Thomas
authors.initials: T
authors.lastname: Fréour
authors.forename: Célia
authors.initials: C
authors.lastname: Ravel
authors.forename: Miguel
authors.initials: M
authors.lastname: Jean
authors.forename: Agnès
authors.initials: A
authors.lastname: Colombel
authors.forename: Emile
authors.initials: E
authors.lastname: Daraï
authors.forename: Paul
authors.initials: P
authors.lastname: Barrière
mesh_terms: D000328:Adult; D000367:Age Factors; D015992:Body Mass Index; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D056826:Single Embryo Transfer / Q000379:methods*; D012907:Smoking / Q000009:adverse effects; D047929:Term Birth