Acute pancreatitis in pregnancy (APIP), which was thought to be a rare but severe disease, with a high perinatal mortality among maternal-fetuses. Our research aimed to study and assess thyroid injury in a rat model of APIP and its possible mechanisms. The APIP model was established by retrograde injection with sodium taurocholate. Sham-operated (SO) and APIP groups were performed at 3 time-points. Histological changes in the maternal thyroid and pancreas were assessed. The activities of serum amylase, lipase and levels of FT3, FT4, MDA, TNF-alpha and IL-1 beta were detected in maternal rats, and the expression of MIF, ICAM-1 and CD68 in the maternal thyroids were determined. In this study, maternal thyroid injury as well as pancreas injury occurred in a time-dependent manner. The activities of serum amylase, lipase and levels of MDA, TNF-alpha and IL-1 beta were markedly increased in acute pancreatitis rats, the levels of serum FT3 and FT4 were obviously decreased in APIP groups, and the expressions of MIF, ICAM-1 and CD68 were significantly increased in the thyroid of the APIP group. Ultrastructural thyroid injuries were observed in the APIP group. Our research suggests that thyroid injury is involved in the rat experimental model of APIP. The degree of thyroid dysfunction is associated with APIP, which may affect the prognosis of acute pancreatitis. (C) 2018 Elsevier Inc. All rights reserved.