title: A Comparison of the Effects of Transdermal Estradiol and Estradiol Valerate on Endometrial Receptivity in Frozen-thawed Embryo Transfer Cycles: A Randomized Clinical Trial.
abstract: BACKGROUND
  The purpose of this study was to determine the optimal endometrial preparation protocol by comparing the clinical outcome of two methods of endometrial preparation in frozen-thawed embryo transfer (FET) cycles, including that is, oral estradiol and 17ß-estradiol transdermal patch.
  
  
  METHODS
  In this randomized controlled trial, women underwent either conventional IVF or intracytoplasmic sperm injection (ICSI) who had at least two top-quality embryos appropriate for cryopreservation and frozen embryos from previous cycles. In the study group (n=45), 17-B estradiol transdermal patches 100 μg were applied from the second day of the cycle and continued every other day. Then, each patch was removed after four days. In the control group (n=45), oral estradiol valerate 6 mg was started at the same time and continued daily.
  
  
  RESULTS
  There was a significant difference in estradiol level on the day of progesterone administration and the day of embryo transfer between the two groups (p= 0.001 in both), but no significant difference was observed between them in biochemical and clinical pregnancy rates (32.6% vs. 33.3%, p=1.000 and 30.2% vs. 33.3%, p=0.810, respectively).
  
  
  CONCLUSIONS
  It is suggested that estradiol transdermal patches be used instead of oral estradiol in FET cycles. Due to the reduced costs, drug dose, and emotional stress as well as the simplicity of the protocol for patients.
authors.affiliation: Research and Clinical Center for Infertility, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors.forename: Robab
authors.initials: R
authors.lastname: Davar
authors.affiliation: Research and Clinical Center for Infertility, Dezful University of Medical Sciences, Dezful, Iran.
authors.forename: Sima
authors.initials: S
authors.lastname: Janati
authors.affiliation: Research and Clinical Center for Infertility, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors.forename: Fereshteh
authors.initials: F
authors.lastname: Mohseni
authors.affiliation: Department of Epidemiology, Faculty of Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Khabazkhoob
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Soheila
authors.initials: S
authors.lastname: Asgari
keywords: Endometrial preparation; Frozen-thawed embryo transfer; Pregnancy rate; Transdermal estradiol patchs