[Fever as etiology of temporary infertility in the man]

Fever of > or = 39 degrees C for > or = 3 days can lead to severely impaired semen quality and even azoospermia. Among spermatogenic cells, pachytene spermatocytes and spermatids are particularly sensitive to temperature. Because of the nature of a spermatogenic cycle, impairment of semen quality becomes obvious after a latent period of several weeks. The changes are usually reversible within a few months. Therefore, a careful history with regard to fever episodes during preceding 3 months is mandatory for interpretation of semen analysis.

Five patients are reported who desired a child and had experienced high fever of > or = 39 degrees C for > or = 3 days. The results of semen analyses are presented in relation to fever episodes.

Sperm concentration declined to 0.4-7% and fast progressive motility to 0-23% 3-6 weeks after the fever episodes and returned to base line levels within 4-6 months. In patients without semen analysis before the fever episode, semen quality remarkably improved thereafter.

Investigating patients for a history of fever during the 3 months preceding fertility work-up avoids unreasonable treatment recommendations based on transient impairment of semen quality.