title: Day 3 embryo transfer may have better pregnancy outcomes in younger than 35-year-old patients with poor ovarian response.
abstract: OBJECTIVE
  To explore the pregnancy outcomes of embryo transfer with D2 or D3 embryos in patients with poor ovarian response.
  
  
  METHODS
  The pregnancy outcomes of 620 patients who had poor ovarian response and underwent the first in vitro fertilization-embryo transfer (IVF-ET) were retrospectively analyzed. Of the 620 cycles, all available fresh D2 embryos were used in 365 cycles (day 2 embryo transfer) and all available fresh D3 embryos were used in 255 cycles (day 3 embryo transfer) without superfluous embryos for freezing.
  
  
  RESULTS
  There was a significant difference in clinical pregnancy rate between day 2 (32.73 %) and day 3 (50.83 %) embryo transfer in younger than 35-year-old patients, but no significant differences in implantation rate, live birth rate and spontaneous abortion rate (P > 0.05). There were similar pregnancy outcomes between day 2 and 3 embryo transfer in 35-year and older patients.
  
  
  CONCLUSIONS
  D3 embryo transfer may have better pregnancy outcomes in younger than 35-year-old patients with poor ovarian response.
authors.affiliation: Reproductive Medical Center, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China.
authors.forename: Zhi-min
authors.initials: ZM
authors.lastname: Xin
authors.forename: Bin
authors.initials: B
authors.lastname: Xu
authors.forename: Hai-xia
authors.initials: HX
authors.lastname: Jin
authors.forename: Wen-yan
authors.initials: WY
authors.lastname: Song
authors.forename: Ying-pu
authors.initials: YP
authors.lastname: Sun
mesh_terms: D000022:Abortion, Spontaneous; D000328:Adult; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008423:Maternal Age; D010053:Ovary / Q000503:physiopathology*; D010062:Ovulation Induction; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D012189:Retrospective Studies