Background: Gardnerella vaginalis (GV) is most frequently associated with bacterial vaginosis and is the second most common etiology causing intrauterine infection after Ureaplasma urealyticum . Intrauterine GV infection adversely affects pregnancy outcomes, resulting in preterm birth, fetal growth restriction, and neonatal pneumonia. The knowledge of how GV exerts its effects is limited. We developed an in vivo A survival mini-laparotomy was conducted on New Zealand rabbits on gestational day 21 (28 weeks of human pregnancy). In each dam, fetuses in the right uterine horn received intra-amniotic 0.5 × 10 Materials and Methods: A survival mini-laparotomy was conducted on New Zealand rabbits on gestational day 21 (28 weeks of human pregnancy). In each dam, fetuses in the right uterine horn received intra-amniotic 0.5 × 10 2 Three dams with a combined total of 12 fetuses were exposed to intra-amniotic GV, and 9 fetuses were unexposed. The weights of fetuses, placenta, and fetal lung were significantly lower in the GV group than the saline-inoculated control group [mean gross weight, GV (19.8 ± 3.8 g) vs. control (27.9 ± 1.7 g), Results: Three dams with a combined total of 12 fetuses were exposed to intra-amniotic GV, and 9 fetuses were unexposed. The weights of fetuses, placenta, and fetal lung were significantly lower in the GV group than the saline-inoculated control group [mean gross weight, GV (19.8 ± 3.8 g) vs. control (27.9 ± 1.7 g), p < 0.001; mean placenta weight, GV (5.5 ± 1.0 g) vs. control (6.5 ± 0.7 g), p = 0.027; mean fetal lung weight, GV (0.59 ± 0.11 g) vs. control (0.91 ± 0.08 g), p = 0.002. There was a two-fold increase in the multinucleated syncytiotrophoblasts in the placenta of the GV group than their littermate controls (82.9 ± 14.9 vs. 41.6 ± 13.4, p < 0.001). The mean alveolar septae of GV fetuses was significantly thicker than the control (14.8 ± 2.8 μm vs. 12.4 ± 3.8 μm, p = 0.007). Correspondingly, the proliferative index in the interalveolar septum was 1.8-fold higher in the GV group than controls (24.9 ± 6.6% vs. 14.2 ± 2.9%, p Low-dose intra-amniotic GV injection induces fetal growth restriction, increased placental multinucleated syncytiotrophoblasts and fetal lung re-modeling characterized by alveolar septal hypertrophy with cellular proliferative changes. Discussion: This intra-amniotic model could be utilized in future studies to elucidate the acute and chronic effects of GV intrauterine infections.Conclusion: This intra-amniotic model could be utilized in future studies to elucidate the acute and chronic effects of GV intrauterine infections., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Cheah, Lai, Tan, Swaminathan, Wong, Wong and Tan.)