Background/Objectives: Infertility affects couples at reproductive age, with in vitro fertilization (IVF) being the most effective treatment. Success rates of IVF are influenced by several factors, including a healthy female reproductive system microbiome, which can improve implantation rates and pregnancy outcomes. This study evaluated the impact of Ligilactobacillus salivarius PS11610 on IVF outcomes. This strain showed antimicrobial activity against pathogens related to dysbiosis, commonly observed in women undergoing assisted reproductive treatment. Results: The administration of L. salivarius PS11610 at a dose of 1 × 10⁹ CFU every 12 h for at least one month before IVF procedures, particularly in the frozen embryo transfer (FET) group, appears to enhance the success rate of IVF. IVF procedures without embryo transfer showed no significant differences between the groups. However, there were statistically significant differences in the quality of embryos, specifically in category 2, which were higher in the group without L. salivarius PS11610 supplementation (p = 0.042). Similar results were seen in the IVF with embryo transfer group, where the quality of embryos in categories 2 and 3 was higher in the group without L. salivarius PS11610 (p = 0.019 and p = 0.05, respectively). IVF with FET showed notable improvements, where intake of L. salivarius PS11610 was associated with a significant increase in live birth infants (26.4% with L. salivarius PS11610 vs. 17.9% without, p = 0.034) and higher biochemical pregnancy rates (42.6% vs. 34%, p = 0.071). Conclusions: Despite some differences in embryo quality, the overall positive impact on pregnancy and birth outcomes highlights L. salivarius PS11610 as a promising supplement in assisted reproductive treatments.