title: Poor implantation of cryopreserved reinsemination-fertilized human embryos.
abstract: OBJECTIVE
  To investigate whether a poor rate of implantation after in vitro fertilization (IVF) was due to poor embryonic/endometrial synchrony during the original IVF cycle, we have cryopreserved reinseminated-fertilized embryos for later more synchronous replacement after thawing. The chance of implantation of fresh reinseminated fertilized human oocytes is approximately one tenth that of timely fertilized embryos. STUDY DESIGN AND DATA: Retrospective study of 35 original oocyte collections in which initial normal fertilization was 47.3% (129/273 oocytes), with 49.6% fertilization (67/135) upon reinsemination. Of these, 70 initially fertilized and 67 reinsemination-fertilized embryos were cryopreserved, and 50 initially fertilized and all 67 reinsemination-fertilized embryos were subsequently thawed with 72% and 63% cryosurvival, respectively, (not significant).
  
  
  METHODS
  Private infertility clinic.
  
  
  RESULTS
  In 11 cycles, 23 thawed initially fertilized embryos (group A) were replaced with a 21.7% implantation rate per embryo; in 10 cycles, 13 initially fertilized and 12 reinsemination-fertilized embryos (group B) were replaced together with an 8% implantation rate; finally, in 16 cycles, 30 reinsemination-fertilized embryos (group C) were replaced with a 3.3% implantation rate (group A versus group C: P = 0.076). Comparison of clinical pregnancies between these groups was significantly different (6/11 versus 1/16; P = 0.0427).
  
  
  CONCLUSIONS
  Reinsemination-fertilized embryos survive freezing as well as initially fertilized embryos, but better embryonic/endometrial synchrony does not improve chances of their implantation.
authors.affiliation: Reproductive Biology Associates, Atlanta, Georgia 30342.
authors.forename: M
authors.initials: M
authors.lastname: Tucker
authors.forename: C
authors.initials: C
authors.lastname: Elsner
authors.forename: H
authors.initials: H
authors.lastname: Kort
authors.forename: J
authors.initials: J
authors.lastname: Massey
authors.forename: D
authors.initials: D
authors.lastname: Mitchell-Leef
authors.forename: A
authors.initials: A
authors.lastname: Toledo
mesh_terms: D000328:Adult; D002470:Cell Survival; D015925:Cryopreservation; D010064:Embryo Implantation; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D012189:Retrospective Studies