The co-formulated, ritonavir-boosted protease inhibitor lopinavir is a frequently used component of HAART for treatment of HIV-infected women during pregnancy and prevention of mother-to-child transmission. We performed a systematic review to assess the effects of lopinavir/ritonavir on maternal and infant clinical and safety outcomes in HIV-infected pregnant women. PubMed, EMBASE, and select congresses were searched for studies published through May 31, 2012. Studies were selected that included HIV-infected pregnant mothers treated with a lopinavir/ritonavir-based regimen and described relevant maternal and infant outcomes. Ten articles or presentations describing nine studies were identified, comprising 2,675 lopinavir/ritonavir-treated women. In studies reporting HIV-1 RNA at delivery, HIV-1 RNA < 200 to < 1,000 copies/ml was achieved in 64-97% of subjects. Preterm delivery (< 37 weeks gestation) rates ranged from 8.3 to 25%; low birth weight (< 2,500 g) rates ranged from 11 to 20.3%. In one study, preterm delivery rates and low birth weight were similar between women who received standard or increased doses of lopinavir/ritonavir. In five studies reporting stillbirths and live births, 38 stillbirths occurred versus 2,058 live births (1.8%) among women receiving lopinavir/ritonavir. In eight studies reporting mother-to-child transmission at different time points, rates ranged from 0 to 3.3% and appeared to be similar in the one study comparing pregnant women who received standard or higher doses of lopinavir/ritonavir. The results from this systematic review suggest no unique safety or efficacy concerns with use of standard dose lopinavir/ritonavir as part of HAART in pregnant women.