Self-reported mechanical problems during condom use and semen exposure : Comparison of two randomized trials in the United States of America and Brazil

The objective was to compare self-reported condom use problems and objectively determined semen exposure in 2 populations. Two randomized crossover trials in the United States and Brazil compared the failure rates of the female condom (FC) and male condom (MC). Participants used both condom types completed condom-specific questionnaires to report problems and collected precoital and postcoital samples of vaginal fluid. Prostate-specific antigen (PSA) was detected by immunoassay. Problems with condom use were reported less frequently in the Brazilian study (rate difference: FC = 24% P <0.0001 MC = 5% P = 0.003). By contrast the PSA detection rates were similar for both the FC and the MC (rate difference: FC = 2% MC = 1% not significant). These results suggest that the PSA detection rate was similar in the 2 study groups and that self-reported problems may be a less reliable measure of condom failure. Use of biomarkers of condom failure like PSA may help to strengthen the validity of studiespromoting behavior change for the prevention of sexually transmitted diseases. (authors)