Little is known about how the information presented in the informed consent process influences study outcomes among participants. This study examines the influence of informed consent content on reported baseline contraceptive knowledge and concerns among two groups of HIV-serodiscordant and seroconcordant HIV-positive couples enrolled in research projects at an HIV research center in Lusaka, Zambia. We found significant differences in the reporting of contraceptive knowledge and concerns between couples viewing consent materials that included detailed information about contraception and those viewing consent materials that lacked the detailed information. We conclude that the design of informed consent materials should strike a balance between ensuring that participants give truly informed consent and educating participants in ways that do not compromise the assessment of the impact of behavioral interventions.