title: Sperm morphology: classification drift over time and clinical implications.
abstract: OBJECTIVE
  To assess sperm morphology with Tygerberg (strict) and World Health Organization (WHO) 3rd criteria for intrauterine inseminations (IUI) between two eras to determine if there was a difference in pregnancy rates.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Academic institution.
  
  
  METHODS
  127 couples with 290 IUI treatments during 1996-97 (era 1) and 133 couples with 317 IUI treatments during 2005-06 (era 2).
  
  
  METHODS
  None.
  
  
  METHODS
  Pregnancy rates per cycle and couple.
  
  
  RESULTS
  Average sperm morphology was higher in era 1 than era 2 for both WHO 3rd (37 ± 13% vs. 23 ± 10%) and strict criteria (8.0 ± 5.0% vs. 4.0 ± 3.0%). Pregnancy rates per cycle were 5.9% versus 19.8% in era 1 and 16.7% versus 19.3% in era 2 for couples with WHO 3rd morphology <30% or ≥30%, respectively. Pregnancy rates per cycle were 2.7% versus 15.0% in era 1 and 13.3% versus 14.7% in era 2 for couples with strict morphology ≤4% or >4%, respectively.
  
  
  CONCLUSIONS
  There was a strong relationship between morphology and IUI outcome in era 1 that was not present in era 2. These results suggest that classification drift increased the percentage of men diagnosed with teratozoospermia and resulted in a loss of predictive value.
authors.affiliation: Department of Obstetrics and Gynecology, Mayo Clinic, Rochester, Minnesota 55905, USA. morbeck.dean@mayo.edu
authors.forename: Dean E
authors.initials: DE
authors.lastname: Morbeck
authors.forename: Phoebe H
authors.initials: PH
authors.lastname: Leonard
authors.forename: Amy L
authors.initials: AL
authors.lastname: Weaver
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Shimek
authors.forename: Esther V A
authors.initials: EV
authors.lastname: Bouwsma
authors.forename: Charles C
authors.initials: CC
authors.lastname: Coddington
mesh_terms: D000328:Adult; D048430:Cell Shape / Q000502:physiology; D005260:Female; D006801:Humans; D007248:Infertility, Male / Q000175:diagnosis* / Q000209:etiology; D007315:Insemination, Artificial; D008297:Male; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D055101:Semen Analysis / Q000379:methods* / Q000639:trends*; D013094:Spermatozoa / Q000145:classification* / Q000166:cytology*; D013997:Time Factors