Objective: To determine the frequency of and factors associated with delayed vasectomy success in men with first postvasectomy semen analysis showing motile sperm.
Design: Descriptive study.
Setting: One hospital-based family planning clinic and two private clinics from the Quebec City area, Canada.
Patient(s): Three hundred nine men vasectomized between 1990 and 2001 and who had a first semen analysis showing motile sperm.
Intervention(s): None.
Main outcome measure(s): Vasectomy success, based on the last available semen analysis-either in the medical record or as requested for the study-and on sterility as established by a telephone-based questionnaire in 2003.
Result(s): Among the 309 men, 174 (56.3%, 95% confidence interval 50.7%-61.7%) had delayed vasectomy success. Significant independent factors associated with delayed vasectomy success were lower sperm count in the first postvasectomy semen analysis and shorter interval between vasectomy and first postvasectomy semen analysis.
Conclusion(s): Delayed vasectomy success occurs in more than half of men with a first postvasectomy semen analysis showing motile sperm. The decision to repeat vasectomy should not rely on a single semen analysis showing motile sperm.