title: The presence of pinopodes in the human endometrium does not delineate the implantation window.
abstract: OBJECTIVE
  To assess pinopode formation in human endometrium during the luteal phase of the menstrual cycle and in the first trimester of pregnancy.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  Outpatient infertility clinics and outpatient family planning clinic.
  
  
  METHODS
  Thirty-two regularly cycling infertile women, 15 regularly cycling fertile women, 9 women receiving elective termination of pregnancy, and 1 woman receiving GnRH agonist and hormone therapy addback.
  
  
  METHODS
  Endometrial tissue was collected by suction pipelle and examined by scanning electron microscopy for pinopode formation.
  
  
  METHODS
  Endometrial tissue was scored (0, 1, 2, 3, or 4) depending on the percentage of the surface covered in pinopodes (from 0% to >20% of 100 fields).
  
  
  RESULTS
  Pinopodes were present throughout the luteal phase of the menstrual cycle, up to the 11th week of pregnancy, and in the endometrium of the woman on GnRH agonist and hormone therapy.
  
  
  CONCLUSIONS
  Pinopodes can be detected in the progesterone-exposed endometrium for an extended period of time, in contradistinction to the perception that they are markers for the implantation window in the human endometrium.
authors.affiliation: Division of Reproductive Sciences, Samuel Lunenfeld Research Institute, and the Fran and Lawrence Bloomberg Department of Obstetrics and Gynecology, Mount Sinai Hospital, Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Claire
authors.initials: C
authors.lastname: Quinn
authors.forename: Edward
authors.initials: E
authors.lastname: Ryan
authors.forename: E Anne
authors.initials: EA
authors.lastname: Claessens
authors.forename: Ellen
authors.initials: E
authors.lastname: Greenblatt
authors.forename: Peter
authors.initials: P
authors.lastname: Hawrylyshyn
authors.forename: Barbara
authors.initials: B
authors.lastname: Cruickshank
authors.forename: Thomas
authors.initials: T
authors.lastname: Hannam
authors.forename: Caroline
authors.initials: C
authors.lastname: Dunk
authors.forename: Robert F
authors.initials: RF
authors.lastname: Casper
mesh_terms: D000328:Adult; D021961:Cell Membrane Structures / Q000648:ultrastructure*; D010064:Embryo Implantation / Q000502:physiology; D004624:Embryo Transfer; D004717:Endometrium / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D008183:Luteal Phase / Q000502:physiology; D011247:Pregnancy; D011446:Prospective Studies; D013997:Time Factors