This is an open-label, randomised controlled trial of DTG versus EFV -based regimens for 250 women commencing cART in late pregnancy, randomised 1:1 to DTG vs EFV-based cART. The purpose of this study is to inform treatment guidelines and for the first time specifically address the treatment needs of this group of women- hence the trial is powered for superiority over EFV. The primary endpoints is maternal VL at delivery, with secondary endpoints including safety and tolerability of DTG in both mother and infant, VL decline in breast milk, development of drug resistance, pharmacokinetics of DTG in mother-infant pairs, pharmacogenomics factors relating to efficacy or toxicity of DTG, and MTCT of HIV up to 72 weeks postpartum. Two sites have been selected - Infectious Diseases Institute, Makerere University, Kampala, Uganda and the University of Cape Town, South Africa - both have a strong track record of successfully delivering collaborative multidisciplinary research in PMTCT. Furthermore, health economics analysis to examine costs and cost-effectiveness of DTG in late-presenting pregnant women will be conducted