“…Several studies have shown that previous infection with C. trachomatis influenced neither the spermiogram (Eggert-Kruse et al, 1990) nor the IVF outcome (Torode et al, 1987, Driscoll et al, 1991, Lessing et al, 1991. Forman et al (1987) took samples at five different stages during an IVF procedure and analysed them for bacteriological contaminations: (i) ejaculate; (ii) semen pellet after washing and centrifugation; (iii) swim-up suspension; (iv) insemination medium after the first 24 h of embryo culture; (v) culture medium after another 24 h of culture. Thus, bacteriological analyses after swim-up (Wong et al, 1986) and Percoll gradient centrifugation (Mathieu et al, 1988) had negative results.…”