title: Optimizing the number of blastocyst stage embryos to transfer on day 5 or 6 in women 38 years of age and older: a Society for Assisted Reproductive Technology database study.
abstract: OBJECTIVE
  To develop evidence-based recommendations for the optimum numbers of blastocyst stage embryos to transfer in women >or=38 years old.
  
  
  METHODS
  Retrospective analysis of national Society for Assisted Reproductive Technology data from 2000 to 2004.
  
  
  METHODS
  National writing group.
  
  
  METHODS
  Five thousand five hundred sixty-nine day 5 and day 6 ETs in women >or=38 years of age undergoing their first assisted reproductive technology cycle.
  
  
  METHODS
  None.
  
  
  METHODS
  Logistic regression was used to model the probability of a delivery, twins, and high-order multiples based on patient characteristics.
  
  
  RESULTS
  In 38- and 39-year-old women there was an increase in delivery rates up to transfer of two embryos. Beyond that, number transferred increased multiple rates but not delivery rates. Transfer of three embryos in 40-year-old women increased delivery but not multiple rate. For 41- to 42-year-olds delivery rate was level after transfer of three, but twin rate continued to increase. Multivariate analysis showed that age, embryo cryopreservation, and use of intracytoplasmic sperm injection influence delivery rate. Increasing numbers of oocytes retrieved showed a trend but was not an independent predictor.
  
  
  CONCLUSIONS
  Optimal numbers of blastocyst stage embryos to transfer in first cycles for women 38 to 39 years old differ from those in women >or=40 years. Number transferred should be modified as determined by a model that includes availability of excess embryos to cryopreserve, use of intracytoplasmic sperm injection, and, possibly, number of oocytes retrieved.
authors.affiliation: Department of Obstetrics and Gynecology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA. judy.stern@dartmouth.edu
authors.forename: Judy E
authors.initials: JE
authors.lastname: Stern
authors.forename: Marlene B
authors.initials: MB
authors.lastname: Goldman
authors.forename: Harry
authors.initials: H
authors.lastname: Hatasaka
authors.forename: Todd A
authors.initials: TA
authors.lastname: MacKenzie
authors.forename: Catherine
authors.initials: C
authors.lastname: Racowsky
authors.forename: Eric S
authors.initials: ES
authors.lastname: Surrey
mesh_terms: D000328:Adult; D000375:Aging; D001755:Blastocyst / Q000502:physiology*; D016208:Databases, Factual; D036861:Delivery, Obstetric / Q000706:statistics & numerical data; D010064:Embryo Implantation / Q000502:physiology; D004624:Embryo Transfer / Q000379:methods*; D047108:Embryonic Development / Q000502:physiology; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods* / Q000706:statistics & numerical data*; D006801:Humans; D007248:Infertility, Male / Q000453:epidemiology; D008297:Male; D011247:Pregnancy; D012044:Regression Analysis; D027724:Reproductive Techniques, Assisted / Q000706:statistics & numerical data; D012189:Retrospective Studies; D014427:Twins; D014481:United States