The contribution of a hidden male factor to unexplained infertility

Antonio Mackenna, Christopher L. R. Barratt, Efrossini Kessopoulou, Ian Cooke

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)


OBJECTIVE: To assess sperm function in patients with unexplained infertility in comparison with normal fertile men.

DESIGN: Prospective study.

SETTING: Infertility outpatient clinic and donor insemination program, University Department of Obstetrics and Gynecology at the Jessop Hospital for Women, Sheffield, United Kingdom.

PATIENTS: Nineteen patients with unexplained infertility and nineteen normal fertile men from a donor insemination program.

MAIN OUTCOME MEASURES: Monitoring of reactive oxygen species generation; computerized assessment of the hyperactivated motility pattern of the spermatozoa under capacitating conditions, with and without the addition of follicular fluid (FF); evaluation of sperm-zona pellucida (ZP) binding.

RESULTS: Reactive oxygen species generation was not significantly different between the study and control group. Follicular fluid-induced hyperactivation (HA) was significantly lower in patients with unexplained infertility than in the donors, but no difference was found comparing spontaneous HA (without FF) between the two groups. Follicular fluid-induced HA was completely absent in 39% of infertile men and only one fertile man. A low sperm-ZP binding ratio (< or = 0.3) was observed in 28% (5/18) of patients with unexplained infertility. In all, nine infertile men (47%) had 0% FF-induced HA and/or low sperm-ZP binding ratio.

CONCLUSIONS: Assessing FF-induced HA and sperm-ZP binding may have clinical significance in distinguishing a subgroup of men with unexplained infertility with sperm function abnormalities in which the fertilizing capacity of the spermatozoa might be reduced. These patients cannot be identified by the conventional semen analysis. Both tests may also be useful in planning the appropriate treatment for couples with unexplained infertility.

Original languageEnglish
Pages (from-to)405-411
Number of pages7
JournalFertility and Sterility
Issue number2
Publication statusPublished - Feb 1993


  • Female
  • Follicular Fluid/physiology
  • Humans
  • Infertility, Male/etiology
  • Male
  • Reactive Oxygen Species/metabolism
  • Reference Values
  • Sperm Motility
  • Zona Pellucida/physiology


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