Limitations
One limitation of this study is the limited number of validated HIV prevention knowledge measures available. Although widely used and integrated into most national surveys, the UNAIDS measure was developed in 2002 and does not include questions about newer prevention and treatment options. We expanded the UNAIDS Knowledge measure to some extent by adding items about PMTCT. However, our HIV/PMTCT Knowledge Index also suffers from a ceiling effect, with mean scores close to the maximum possible score of 9, especially for the intervention group. Ceiling effects may make identification of the impact of an intervention harder to detect as there is little room for measurable improvement [