title: Influence of endometrial thickness on treatment outcomes following in vitro fertilization/intracytoplasmic sperm injection.
abstract: BACKGROUND
  The study was designed to investigate the roles of endometrial thickness (EMT) at the day of human chorionic gonadotropin (hCG) administration on pregnancy outcomes in a large patient population.
  
  
  METHODS
  This retrospective cohort study included 9,952 patients undergoing their first IVF/ICSI with autologous oocytes from January 2011 to January 2015. Patients were divided into three groups based on the EMT (group A:≤8 mm; group B: 9-14 mm and group C:≥15 mm). Live birth rate (LBR), clinical pregnancy rate (CPR), early miscarriage rate (EMR), and ectopic pregnancy rate (EPR) were analyzed. Additionally, the live birth rate was analyzed for patients with single or double gestational sacs.
  
  
  RESULTS
  Significant differences (p < 0.05) were detected in the LBRs (30.38%, 45.73% and 54.55% for groups A, B, and C, respectively), CPRs (38.57%, 55.04% and 64.32%, respectively), and EPRs (5.58%, 3.48% and 2.19%, respectively), with thicker endometrial thickness favoring all three parameters. However, no differences were found in the EMRs among the three groups (15.64%, 13.44% and 13.05%, respectively, p > 0.05). After adjusting for female age, body mass index (BMI) and endometrial pattern, the multivariate logistic regression analysis demonstrated that the associations between EMT and LBR (adjusted OR: 2.645; 95% CI 2.020-3.464; p < 0.01), CPR (adjusted OR 2.693 95% CI 2.012-3.605 p < 0.01), and EPR (adjusted OR: 0.298 95% CI 0.101-0.713; p < 0.05) were significant. Additionally, live birth rates in the double gestational sac group were different (p < 0.05) among patients with different EMT (72.73%, 87.28%, and 87.36%, respectively), whereas no difference was found in the single gestational sac group. In the double gestational sac group, LBR was positively correlated with increasing endometrial thickness only in patients with twin pregnancies but not in patients with singletons.
  
  
  CONCLUSIONS
  Our study shows that endometrial thickness at the day of hCG administration has an effect on LBR, CPR and EPR, with all three parameters increasing with the EMT. Furthermore, successful twin pregnancies are associated with a thicker endometrium.
authors.affiliation: Department of Reproductive Medical Center, First Affiliated Hospital of Zhengzhou University, JianShe Dong Road, Erqi District, Zhengzhou, Henan Province, People's Republic of China.
authors.forename: Ning-Zhao
authors.initials: NZ
authors.lastname: Ma
authors.affiliation: Department of Reproductive Medical Center, First Affiliated Hospital of Zhengzhou University, JianShe Dong Road, Erqi District, Zhengzhou, Henan Province, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Reproductive Medical Center, First Affiliated Hospital of Zhengzhou University, JianShe Dong Road, Erqi District, Zhengzhou, Henan Province, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Dai
authors.affiliation: Department of Reproductive Medical Center, First Affiliated Hospital of Zhengzhou University, JianShe Dong Road, Erqi District, Zhengzhou, Henan Province, People's Republic of China.
authors.forename: Zhi-Qin
authors.initials: ZQ
authors.lastname: Bu
authors.affiliation: Department of Reproductive Medical Center, First Affiliated Hospital of Zhengzhou University, JianShe Dong Road, Erqi District, Zhengzhou, Henan Province, People's Republic of China.
authors.forename: Lin-Li
authors.initials: LL
authors.lastname: Hu
authors.affiliation: Department of Reproductive Medical Center, First Affiliated Hospital of Zhengzhou University, JianShe Dong Road, Erqi District, Zhengzhou, Henan Province, People's Republic of China. syp2008@vip.sina.com.
authors.forename: Ying-Pu
authors.initials: YP
authors.lastname: Sun
mesh_terms: D000328:Adult; D001723:Birth Rate / Q000639:trends; D015331:Cohort Studies; D004717:Endometrium / Q000000981:diagnostic imaging*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods / Q000639:trends; D006801:Humans; D007247:Infertility, Female / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000628:therapy*; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods / Q000639:trends*; D016896:Treatment Outcome
keywords: Endometrial thickness; Endometrium; IVF/ICSI; Live birth rate