A dolutegravir (DTG)-based antiretroviral regimen has been rolled out for pregnant women in low- and middle-income countries since 2020. However, available safety data are limited to a few clinical trials and observational studies. Hence, we present real-world pregnancy and birth outcome safety data from a large sample multicenter cohort study in Ethiopia. A retrospective cohort study was conducted in fourteen hospitals across Ethiopia from 2017 to 2022. HIV-infected pregnant women were followed from the date of prevention of mother-to-child transmission (PMTCT) care enrolment until the infant was 6-8 weeks old. The primary safety outcome was a composite of adverse pregnancy events comprising spontaneous abortion, intrauterine fetal death (IUFD) before onset of labor, preterm birth, and maternal death. Additionally, a composite adverse birth outcome was assessed, comprising intrapartum fetal demise, low birth weight, and neonatal death. Finally, a composite of adverse pregnancy or birth outcome was also investigated. The exposure of interest was the antiretroviral treatment (ART) regimen used during pregnancy for PMTCT of HIV. During the study period, 2643 women were enrolled in routine PMTCT care. However, 2490 (92.2%) participants were eligible for the study. A total of 136/1724 (7.9%, 95% CI: 6.7-9.3%) women experienced adverse pregnancy outcomes. Fewer women in the DTG-based group (5.4%, 95% CI: 3.7-7.5%) had adverse pregnancy outcomes than in the Efavirenz (EFV)-based group (8.3%, 95% CI: 6.6-10.3%), P = 0.004. After controlling for baseline differences, the DTG group had a 43% lower risk of adverse pregnancy outcomes (adjusted odd ratio (AOR), 0.57; 95% CI, 0.32-0.96%) and a 53% lower risk of preterm birth (AOR, 0.47; 95% CI, 0.22-0.98%) compared to the EFV group. A total of 103/1616 (6.4%, 95% CI: 5.2-7.7%) women had adverse birth outcomes. Although the difference was not statistically significant, fewer women in the DTG group (30/548; 5.5%, 95% CI: 3.7-7.7%) than in the EFV group (57/830; 6.9%, 95% CI: 5.2-8.8%) had adverse birth outcomes. In this study, we observed that DTG-based regimens were associated with better pregnancy and birth outcome safety profiles, reaffirming the WHO recommendation. However, a prospective study is recommended to assess uncaptured maternal and perinatal adverse outcomes, such as congenital abnormalities, and infant growth and neurocognitive development.