title: Role of dilatation and curettage performed for spontaneous or induced abortion in the etiology of endometrial thinning.
abstract: OBJECTIVE
  The aim of this study was to clarify the role of dilatation and curettage (D&C) performed for spontaneous or induced abortion in the etiology of endometrial thinning.
  
  
  METHODS
  This was a retrospective and cross-sectional study of 310 infertile patients from January 2013 through December 2015. Endometrial thickness observed 5-7 days after ovulation in a natural menstrual cycle was correlated with the number of D&C noted in each patient's history.
  
  
  RESULTS
  Study 1 was an investigation of patients without D&C (group A: n = 232) and patients with D&C performed for spontaneous abortion (group B: n = 46). Study 2 was an investigation of patients in group A and patients with D&C performed for induced abortion (group C: n = 32). A significant negative correlation (P < 0.01) between endometrial thickness and number of D&C was observed in both studies. The mean endometrial thickness of the patients in group A was 10.9 ± 2.1 mm. The mean endometrial thickness of the patients in group B with one and ≥two D&C was 7.9 ± 2.3 and 6.9 ± 2.9 mm, respectively. The mean endometrial thickness of the patients in group C with one and ≥two D&C was 9.1 ± 2.3 and 7.8 ± 2.0 mm, respectively. There was a tendency toward gradual endometrial thinning following repeated procedures and the number of previous D&C was significantly associated with endometrial thinning (P < 0.001) in both studies.
  
  
  CONCLUSIONS
  D&C performed for spontaneous or induced abortion may play a causal role in endometrial thinning.
authors.affiliation: Sapporo Endometrium Research, Sapporo, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Azumaguchi
authors.affiliation: Department of Gynecology and Reproductive Endocrinology, KKR Sapporo Medical Center, Tonan Hospital, Sapporo, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Henmi
authors.affiliation: Department of Public Health, Sapporo Medical University, Sapporo, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Ohnishi
authors.affiliation: Department of Obstetrics and Gynecology, Sapporo Medical University, Sapporo, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Endo
authors.affiliation: Department of Obstetrics and Gynecology, Sapporo Medical University, Sapporo, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Saito
mesh_terms: D000028:Abortion, Induced / Q000379:methods*; D000022:Abortion, Spontaneous / Q000601:surgery*; D000328:Adult; D003430:Cross-Sectional Studies; D004107:Dilatation and Curettage / Q000009:adverse effects*; D004717:Endometrium / Q000473:pathology*; D005260:Female; D006801:Humans; D012189:Retrospective Studies
keywords: dilatation and curettage; endometrium; induced abortion; spontaneous abortion; ultrasonography