2013 WHO guidelines for prevention of mother to child transmission recommend combination antiretroviral therapy (ART) for all pregnant women, regardless of CD4 count (Option B/B+). We conducted a retrospective analysis of data from a government-operated HIV clinic in Mbarara, Uganda before and after implementation of Option B+ to assess the impact on retention in care. We limited our analysis to women not on ART at the time of their first reported pregnancy with CD4 count >350. We fit regression models to estimate relationships between calendar period (Option A vs. Option B+) and the primary outcome of interest, retention in care. One thousand and sixty-two women were included in the analysis. Women were more likely to start ART within 6 months of pregnancy in the Option B+ period (68% vs. 7%, p < 0.0001) and had significantly greater increases in CD4 count 1 year after pregnancy (+172 vs. −5 cells, p < 0.001). However, there was no difference in the proportion of women retained in care 1 year after pregnancy (73% vs. 70%, p = 0.34). In models adjusted for age, distance to clinic, marital status, and CD4 count, Option B+ was associated with a nonsignificant 30% increased odds of retention in care at 1 year [adjusted odds ratio (AOR) = 1.30, 95% CI 0.98-1.73, p = 0.06]. After transition to an Option B+ program, pregnant women with CD4 count >350 were more likely to initiate combination therapy; however, interventions to mitigate losses from HIV care during pregnancy are needed to improve the health of women, children, and families.