Background: Despite improved availability of antiretrovirals (ARVs) in sub-Saharan Africa (SSA), vertical HIV transmission continues to result in thousands of HIVinfected infants each year. Contributing to this are barriers to accessing medications and health services that women encounter throughout their reproductive lifespans. This includes before pregnancy (contraceptive non-use), during pregnancy (ARV nonadherence), peripartum (non-hospital deliveries), and postpartum (infant ARV non-use) periods. This dissertation sought to evaluate barriers to preventing vertical HIV transmission throughout women’s reproductive lifespans. Objectives: Specific aims include: 1) assessing associations between gender equitable attitudes and dual contraceptive use among couples with HIV; 2) evaluating the association between maternal ARV adherence and infant ARV administration; and 3) enumerating patient costs of accessing infant HIV care. Methods: Data from three studies were used to achieve these objectives. Aim 1 used cross-sectional data collected from 103 couples in Kenya. Aim 2 used data from a cross-sectional survey (n=384) and focus group discussions (FGDs) (n=6, 5-9 participants each) conducted with HIV-positive mothers in Uganda. Aim 3 used crosssectional and FGD data from 49 HIV-positive mothers in Uganda. Results: Aim 1 findings demonstrated that female and male partner gender equitable attitudes significantly interacted to influence dual contraceptive use (AOR: 1.02, 95% CI: 1.01-1.04). Aim 2 findings showed that infant ARV administration was significantly associated with lack of maternal ARV adherence (AOR: 3.55, 95% CI: 1.36-9.26) and maternal attendance in a support group (AOR: 2.50, 95% CI: 1.06-5.83). FGDs supported these quantitative findings, explaining how support group attendance facilitated ARV administration, while poor ARV health messaging contributed to lack of administration. Finally, aim 3 findings showed that the cost of attending one HIV clinic visit averaged $5.46 USD (SD=$3.63), which is equivalent to 3-4 days’ income. FGDs identified that transportation costs, informal service charges, and opportunity costs contributed to this expense. Conclusions: These results contribute to our understanding of influences on prevention of vertical HIV transmission in SSA. Several recommendations for intervention and further research were identified, including increasing male partner inclusion in reproductive healthcare and improving support for women with HIV. Additionally, cost analyses are needed to support policies assuring access to vertical HIV prevention programs.