Preterm birth, infection, and inflammation advances from the study of animal models

Inflammation is a protective response mediated by both innate and adaptive arms of the immune system following exposure to a range of harmful stimuli. Although inflammation is an essential mechanism in response to challenges including tissue injury and microbiological insult, inappropriate or excessive induction of the inflammatory response is itself a well-characterized cause of morbidity and mortality in adult populations. There is currently a growing appreciation of the potential for inflammation to play an adverse role in fetal health. The expression of cytokines (notably interleukin 1beta [IL-1beta], IL-6, IL-8, and tumor necrosis factor alpha [TNF-alpha]) by either the fetal or maternal tissues has been demonstrated to upregulate the activity of a number of uterine and cervical factors (eg, prostaglandin hormones and their receptors, matrix metalloproteinases, vascular endothelial growth factor [VEGF]), leading to premature initiation of the parturition process. Herein, we review important developments in our understanding of the link between preterm birth and fetal inflammation subsequent to infection, gained from studies undertaken in animal models.