Bacgroud: Although Treg/Th 17 imbalance is reported to play critical roles in the development of adverse pregnancy outcomes in Toxoplasma gondii (T.gondii)-infected mice, information on the detailed mechanisms is still limited.Problem: In the present study, we investigated the expression level of Interleukin (IL)-17 and Foxp3 in relation to the consequent inflammatory response in the placentas ofT.gondii-infected mice, which have adverse pregnancy outcomes.