title: A retrospective cross-sectional study: fresh cycle endometrial thickness is a sensitive predictor of inadequate endometrial thickness in frozen embryo transfer cycles.
abstract: BACKGROUND
  The purpose of this study is to assess predictors of inadequate endometrial cavity thickness (ECT), defined as < 8 mm, in frozen embryo transfer (FET) cycles.
  
  
  METHODS
  This is a retrospective cross-sectional study at an academic fertility center including 274 women who underwent their first endometrial preparation with estradiol for autologous FET in our center from 2001-2009. Multivariable logistic regression was performed to determine predictors of inadequate endometrial development in FET cycles.
  
  
  RESULTS
  Neither age nor duration of estrogen supplementation were associated with FET endometrial thickness. Lower body mass index, nulliparity, previous operative hysteroscopy and thinner fresh cycle endometrial lining were associated with inadequate endometrial thickness in FET cycles. A maximum thickness of 11.5 mm in a fresh cycle was 80% sensitive and 70% specific for inadequate frozen cycle thickness.
  
  
  CONCLUSIONS
  Previous fresh cycle endometrial cavity thickness is associated with subsequent FET cycle endometrial cavity thickness. Women with a fresh cycle thickness of 11.5 mm or less may require additional intervention to achieve adequate endometrial thickness in preparation for a frozen cycle.
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA. patricia.jimenez@utsouthwestern.edu
authors.forename: Patricia T
authors.initials: PT
authors.lastname: Jimenez
authors.forename: Samantha B
authors.initials: SB
authors.lastname: Schon
authors.forename: Randall R
authors.initials: RR
authors.lastname: Odem
authors.forename: Valerie S
authors.initials: VS
authors.lastname: Ratts
authors.forename: Emily S
authors.initials: ES
authors.lastname: Jungheim
mesh_terms: D000328:Adult; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D015925:Cryopreservation / Q000379:methods*; D004624:Embryo Transfer / Q000379:methods*; D004717:Endometrium / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000187:drug effects; D004958:Estradiol / Q000008:administration & dosage; D004967:Estrogens / Q000008:administration & dosage; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D016015:Logistic Models; D008597:Menstrual Cycle; D015999:Multivariate Analysis; D011374:Progesterone / Q000097:blood; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013997:Time Factors; D014463:Ultrasonography
chemical_list: D004967:Estrogens; D011374:Progesterone; D004958:Estradiol