IL6 and abortion: In the mid and late periods of pregnancy, the levels of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), reactive oxygen species (ROS), and other proinflammatory factors increase significantly in the blood of sows (5) and are closely related to numerous diseases, including constipation, abortion, and intrauterine growth retardation (IUGR) (6, 7).