title: Injury to the endometrium prior to the frozen-thawed embryo transfer cycle improves pregnancy rates in patients with repeated implantation failure.
abstract: OBJECTIVE
  This retrospective cohort study evaluated the effectiveness of injury to the endometrium prior to the frozen-thawed embryo transfer (FET) cycle in patients with repeated implantation failure (RIF) in our clinic.
  
  
  METHODS
  Included in this study were 173 patients, aged ≤ 41 years, who failed to become pregnant after repeating fair and/or good embryo transfer more than twice between February 2012 and February 2015. The patients were divided into three groups: Group A (n = 38) underwent soft curettage to the endometrium twice, prior to the FET cycle; Group B (n = 45) underwent hysteroscopy prior to the FET cycle, with no significant factors, such as endometrial polyp; and Group C (n = 90) was the no-treatment group.
  
  
  RESULTS
  The clinical pregnancy rate per transfer was found to be statistically significant between Group A at 42.1% (16/38) and Group C at 22.2% (20/90). The crude and adjusted odds ratios (OR) were 2.55 and 2.49 (95% confidence intervals 1.13-5.78, P = 0.03 and 1.01-6.17, P = 0.048) respectively. Group B with only hysteroscopy had a higher pregnancy rate of 35.6% (16/45) than Group C, but showed no statistical significance (P = 0.103).
  
  
  CONCLUSIONS
  These results suggest that injuring the endometrium has a positive effect on pregnancy.
authors.affiliation: Department of Obstetrics and Gynecology, Kurume University School of Medicine, Fukuoka, Japan.
authors.forename: Emiko
authors.initials: E
authors.lastname: Kanazawa
authors.affiliation: Department of Obstetrics and Gynecology, Kurume University School of Medicine, Fukuoka, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Nakashima
authors.affiliation: Biostatistics Center, Kurume University, Fukuoka, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Yonemoto
authors.affiliation: Kuramoto Women's Clinic, Fukuoka, Japan.
authors.forename: Misako
authors.initials: M
authors.lastname: Otsuka
authors.affiliation: Kuramoto Women's Clinic, Fukuoka, Japan.
authors.forename: Naomi
authors.initials: N
authors.lastname: Yoshioka
authors.affiliation: Kuramoto Women's Clinic, Fukuoka, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kuramoto
authors.affiliation: Department of Obstetrics and Gynecology, Kurume University School of Medicine, Fukuoka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mitao
authors.affiliation: Department of Obstetrics and Gynecology, Kurume University School of Medicine, Fukuoka, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Imaishi
authors.affiliation: Department of Obstetrics and Gynecology, Kurume University School of Medicine, Fukuoka, Japan.
authors.forename: Kan
authors.initials: K
authors.lastname: Komai
authors.affiliation: Department of Obstetrics and Gynecology, Kurume University School of Medicine, Fukuoka, Japan.
authors.forename: Kimio
authors.initials: K
authors.lastname: Ushijima
mesh_terms: D000022:Abortion, Spontaneous; D000328:Adult; D003475:Curettage; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000379:methods*; D004717:Endometrium / Q000000981:diagnostic imaging / Q000293:injuries*; D005260:Female; D006801:Humans; D015907:Hysteroscopy; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies
keywords: endometrial biopsy; endometrial injury; endometrial receptivity; frozen embryo transfer; repeated implantation failure