title: The contribution of a hidden male factor to unexplained infertility.
abstract: OBJECTIVE
  To assess sperm function in patients with unexplained infertility in comparison with normal fertile men.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Infertility outpatient clinic and donor insemination program, University Department of Obstetrics and Gynecology at the Jessop Hospital for Women, Sheffield, United Kingdom.
  
  
  METHODS
  Nineteen patients with unexplained infertility and nineteen normal fertile men from a donor insemination program.
  
  
  METHODS
  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.
authors.affiliation: Department of Obstetrics and Gynecology, University of Sheffield, Jessop Hospital for Women, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Mackenna
authors.forename: C L
authors.initials: CL
authors.lastname: Barratt
authors.forename: E
authors.initials: E
authors.lastname: Kessopoulou
authors.forename: I
authors.initials: I
authors.lastname: Cooke
mesh_terms: D005260:Female; D015571:Follicular Fluid / Q000502:physiology; D006801:Humans; D007248:Infertility, Male / Q000209:etiology*; D008297:Male; D017382:Reactive Oxygen Species / Q000378:metabolism; D012016:Reference Values; D013081:Sperm Motility; D015044:Zona Pellucida / Q000502:physiology
chemical_list: D017382:Reactive Oxygen Species