Objective: To assess the role of varicocele in male infertility.
Design: Data analysis of a large population of couples who were systematically investigated for infertility.
Settings: Couples were recruited in 34 World Health Organization collaborating centers in 24 countries.
Patients: Nine thousand thirty-four men presenting as partner of infertile couples.
Interventions: None.
Main outcome measures: Physical findings, semen characteristics, coincidental pathology, and spontaneous pregnancies.
Results: Varicocele was found in 25.4% of men with abnormal semen, compared with 11.7% of men with normal semen. It was accompanied by decreased testicular volume, impaired sperm quality, and decline of Leydig cell secretion. Spontaneous pregnancies were as frequent in couples in whom the men did or did not have varicocele.
Conclusion: Varicocele is clearly associated with impairment of testicular function and infertility.