Background <p>Antenatal breast milk expression (ABME) is a potential strategy to promote breastfeeding, but its clinical safety and efficacy remain unclear.</p> Objective <p>The study aims to systematically evaluate the impact of ABME on breastfeeding, maternal, and neonatal outcomes.</p> Methods <p>Eleven electronic databases were searched from inception to January 14, 2026, to identify randomized controlled trials (RCTs) investigating ABME. Study quality was assessed using the Cochrane Risk of Bias tool. Heterogeneity was evaluated using the I² statistic and χ² test. Meta-analyses were performed using random-effects models in Review Manager (RevMan version 5.4). The primary outcome was the rate of delayed onset of lactogenesis II (DOL II), defined as copious milk secretion occurring beyond 72&#xa0;h postpartum.</p> Results <p>A total of 3,077 studies were identified. After the removal of duplicates and selection, eleven RCTs studies involving 1,571 women met the inclusion criteria and eight studies were included in the meta-analysis. Compared to the standard care group, women who performed ABME have a lower risk of DOL II in the postpartum period (odds ratio [OR]: 0.30; 95% CI: 0.16–0.56; I² = 24%, Z = 3.71, <i>P</i>&lt;0.01;Number Needed to Treat (NNT) = 8). Furthermore, mothers in the ABME group were significantly more likely to achieve exclusive breastfeeding within the first 24&#xa0;h postpartum (OR: 4.68; 95% CI: 2.43–9.02; <i>P</i> &lt; 0.01; NNT = 4 ). ABME also positively affected exclusive breastfeeding at 1–2 (odds ratio [OR]: 2.59; 95% CI: 1.39–4.8, I² = 0%, Z = 3.01, <i>P</i> = 0.003) and 3–4 weeks postpartum (odds ratio [OR]: 2.53; 95% CI: 1.24–5.15, I² = 29%, Z = 2.55, <i>P =</i> 0.01). Additionally, no significant differences were found between the ABME and standard care group in maternal or infant outcomes.</p> Conclusion <p>ABME effectively reduces the incidence of DOL II and supports early exclusive breastfeeding without compromising maternal or neonatal safety.</p>