Uteroglobin (UG) gene encodes a cytokine-like, multifunctional, antiinflammatory protein, with potent phospholipase A2-inhibitory activity. It has been suggested that during implantation this protein protects the embryos from maternal immunological assault, facilitates the maintenance of quiescence in the uterus throughout pregnancy, prevents the onset of premature labor, and helps maintain an inflammation-free respiratory organ. This latter function of UG is suggested to be accomplished by preventing hydrolysis of surfactant phospholipids by a lung-specific phospholipase A2. Using reverse transcription polymerase chain reaction, in situ hybridization, immunofluorescence, and radioimmunoassay, we studied UG gene expression in the rabbit uterus throughout gestation and in the fetal lung. Here, we report that: (a) contrary to previous reports, UG gene expression in the rabbit uterus occurs throughout gestation with a precipitous decline just before parturition; (b) this gene expression is dramatically increased in the fetal lung with increasing gestational age; and (c) while there is an inverse relationship between the levels of UG, PGE2, and PGF2 alpha, a positive correlation was found in that of UG and leukotriene C4 in the fetal lung. Our results raise the possibility that dysregulation of UG gene expression, at least in part, may contribute to the onset of premature labor and the development of inflammatory lung disease in premature neonates.