Treatment guidelines for HIV-infected pregnant and breastfeeding women have shifted in recent years towards lifelong maternal cART. These changes have led to important reductions in MTCT and are expected to improve maternal HIV outcomes. However, the increasing use of cART during pregnancy has led to challenges. cART's role in causing adverse pregnancy outcomes has been of concern, as has improving postpartum retention in care. In Aim 1a, we evaluated duration of cART during pregnancy's association with LBW due to growth restriction. We found no evidence of an increased risk of LBW for women receiving cART for <8 weeks (RR 1.22, 95% CI: 0.77, 1.91), 9-20 weeks (RR 1.23, 95% CI: 0.82, 1.83), or 21-36 weeks (RR 0.87, 95% CI: 0.22, 3.46), compared to women who never initiated treatment. In Aim 1b, we examined the association between duration of cART during pregnancy through 32 weeks gestation with SGA and preterm birth. We used MO to address measurement error in gestational age. In the complete-case analysis, there was no evidence of an association between duration of cART and SGA or preterm birth. When MO was performed, RRs for SGA moved closer to and past the null, but remained imprecise. For preterm birth, RRs for 9-32 weeks of cART moved away from the null as the variance due to measurement error increased. In Aim 2, we developed a risk score to predict LTFU at 6 months postpartum among women who initiated cART during pregnancy. We observed that 25% of women were LTFU by 6 months postpartum. A risk score cut-point of 11, (42nd percentile) had 85% sensitivity (95% CI 0.82, 0.88) and 22% specificity (95% CI 0.20, 0.24) to detect women LTFU. A risk score cut-point of 18, (69th percentile) identified the 23% of women with the highest probability of LTFU and had sensitivity 32% (95% CI 28%, 36%) and specificity 80% (95% CI 78%, 82%). As lifelong cART increasingly becomes the standard of care, efforts to reduce postpartum LTFU and understand the mechanisms by which cART impacts pregnancy outcomes are essential to sustain improvements in PMTCT and maternal HIV outcomes.