Sperm morphology: Classification drift over time and clinical implications

Dean E. Morbeck, Phoebe H Leonard, Amy L. Weaver, Katherine M. Shimek, Esther V.A. Bouwsma, Charles C. Coddington

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


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. Design: Retrospective study. Setting: Academic institution. Patient(s): 127 couples with 290 IUI treatments during 1996-97 (era 1) and 133 couples with 317 IUI treatments during 2005-06 (era 2). Intervention(s): None. Main Outcome Measure(s): Pregnancy rates per cycle and couple. Result(s): 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. Conclusion(s): 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.

Original languageEnglish (US)
Pages (from-to)1350-1354
Number of pages5
JournalFertility and Sterility
Issue number6
StatePublished - Dec 1 2011


  • Intrauterine insemination
  • Tygerberg strict
  • male infertility
  • semen analysis
  • sperm morphology

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