The effect of Porphyromonas gingivalis lipopolysaccharide on pregnancy in the rat

Objective Periodontitis, mostly associated with Porphyromonas gingivalis , has frequently been related to adverse pregnancy outcomes. We therefore investigated whether lipopolysaccharides of P. gingivalis (Pg‐ LPS ) induced pregnancy complications in the rat. Methods Experiment 1: pregnant rats (day 14) received increasing Pg‐ LPS doses (0.0–50.0 μg kg −1 bw; n  = 2/3 p per dose). Maternal intra‐aortic blood pressure, urinary albumin excretion, placental and foetal weight and foetal resorptions were documented. Experiment 2: 10.0 μg kg −1 bw (which induced the highest blood pressure together with decreased foetal weight in experiment 1) or saline was infused in pregnant and non‐pregnant rats ( n  = 7/9 p per group). Parameters of experiment 1 and numbers of peripheral leucocytes as well as signs of inflammation in the kidney and placenta were evaluated. Results Pg‐ LPS infusion in pregnant rats increased maternal systolic blood pressure, reduced placental weight (dose dependently) and decreased foetal weight and induced foetal resorptions. It, however, did not induce proteinuria or a generalised inflammatory response. No effects of Pg‐ LPS were seen in non‐pregnant rats. Conclusion Pg‐ LPS increased maternal blood pressure, induced placental and foetal growth restriction, and increased foetal resorptions, without inducing proteinuria and inflammation. Pg‐ LPS may therefore play a role in pregnancy complications induced by periodontitis.