title: Density and distribution of primordial follicles in single pieces of cortex from 21 patients and in individual pieces of cortex from three entire human ovaries.
abstract: BACKGROUND
  At the time of cryopreservation of ovarian tissue for fertility preservation a small biopsy of ovarian cortex is usually taken for histological evaluation of the follicular reserve. The purpose of this study was to evaluate the distribution and density of primordial follicles in single pieces of cortex from individual patients and in pieces of cortex comprising entire ovaries, all prepared for cryopreservation.
  
  
  METHODS
  Cortical biopsies from 21 patients and the whole cortex of one ovary were evaluated histologically prior to cryopreservation. In addition, the cortex of two whole ovaries was cryopreserved before histological evaluation. The volume of each cortical fragment was measured, all follicles counted and the follicular density calculated.
  
  
  RESULTS
  In individual pieces of cortex follicular density showed a significant inverse linear correlation with age. The follicular density per cortical fragment prepared from each of the three entire ovaries varied from 1.8 to 166, 0.007 to 140 and 0.04 to 4.48 follicles/mm(3) cortical tissue.
  
  
  CONCLUSIONS
  The density of primordial follicles varied more than two orders of magnitude in cortical fragments from each of the three ovaries. Primordial follicles were very unevenly distributed throughout the cortex of these ovaries, although a significant linear correlation between age and follicular density was found.
authors.affiliation: Laboratory of Reproductive Biology, section 5712, The Fertility Clinic, section 4071, University Hospital of Copenhagen, Rigshospitalet, Denmark. rh12735@rh.dk
authors.forename: K L T
authors.initials: KL
authors.lastname: Schmidt
authors.forename: A G
authors.initials: AG
authors.lastname: Byskov
authors.forename: A
authors.initials: A
authors.lastname: Nyboe Andersen
authors.forename: J
authors.initials: J
authors.lastname: Müller
authors.forename: C
authors.initials: C
authors.lastname: Yding Andersen
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging; D001706:Biopsy; D002648:Child; D015925:Cryopreservation; D005260:Female; D005298:Fertility; D006801:Humans; D009369:Neoplasms / Q000628:therapy; D006080:Ovarian Follicle / Q000033:anatomy & histology*; D010053:Ovary / Q000033:anatomy & histology*