title: Maximizing pregnancy rates and limiting higher-order multiple conceptions by determining the optimal number of embryos to transfer based on quality.
abstract: OBJECTIVE
  To define statistical thresholds for the number of embryos to be transferred to achieve an optimal pregnancy rate and keep higher-order multiple conceptions (pregnancy with more than two fetal sacs with cardiac activity) within an acceptable limit.
  
  
  METHODS
  A retrospective review of patient records.
  
  
  METHODS
  Private practice assisted reproductive technology (ART) facility.
  
  
  METHODS
  Seven hundred fifty-four consecutive patients who underwent IVF-ET from 1994-1996.
  
  
  METHODS
  Embryo grading and score system used on day 3 of embryo transfer.
  
  
  METHODS
  Implantation, pregnancy, and multiple conception rates.
  
  
  RESULTS
  For women < or =35 years old, transfer of up to four poor-quality, two fair-quality, or two good-quality embryos is optimal to eliminate any risk of higher-order multiple pregnancies. Transfer of four poor-quality, three fair-quality, or two good-quality embryos is recommended for women 36 to 39 years old. In women who are > or =40 years old, five embryos need to be transferred regardless of embryo quality.
  
  
  CONCLUSIONS
  The mean cumulative embryo score can be used as a reference to determine an optimal number of embryos to transfer and to predict pregnancy outcome.
authors.affiliation: Northwest Center for Infertility and Reproductive Endocrinology, Margate, Florida 33063, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Hu
authors.forename: W S
authors.initials: WS
authors.lastname: Maxson
authors.forename: D I
authors.initials: DI
authors.lastname: Hoffman
authors.forename: S J
authors.initials: SJ
authors.lastname: Ory
authors.forename: S
authors.initials: S
authors.lastname: Eager
authors.forename: J
authors.initials: J
authors.lastname: Dupre
authors.forename: C
authors.initials: C
authors.lastname: Lu
mesh_terms: D000328:Adult; D015331:Cohort Studies; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods / Q000592:standards; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple / Q000706:statistics & numerical data*; D012189:Retrospective Studies