We evaluated the effect of an option B-plus Enhanced Adherence Package (BEAP), on early ART uptake in a randomized controlled trial. HIV-positive, ART naïve pregnant women in Lusaka, Zambia, were randomized to receive BEAP (phone calls/home visits, additional counseling, male partner engagement and missed-visit follow-up) versus standard of care (SOC). The primary outcome was initiating and remaining on ART at 30 days. Analysis was by intention to treat (ITT) using logistic regression. Additional per protocol analysis was done. We enrolled 454 women; 229 randomized to BEAP and 225 to SOC. Within 30 days of eligibility, 445 (98.2%) initiated ART. In ITT analysis, 82.5% BEAP versus 80.4% SOC participants reached primary outcome (crude relative risk [RR] 1.03; 95% confidence interval [CI] 0.91–1.16; Wald test statistic = 0.44; p-value = 0.66). In per protocol analysis, (92 participants (40.2%) excluded), 91.9% BEAP versus 80.4% SOC participants reached primary outcome (crude RR 1.14; 95% CI 1.02–1.29; Wald test statistic = 2.23; p-value = 0.03). Early ART initiation in pregnancy was nearly universal but there was early drop out suggesting need for additional adherence support. This trial was registered at ClinicalTrials.gov (trials number NCT02459678) on May 14, 2015.