Modelling external light transmission through to the human fetus

Abstract

Little is known about the visual experience of human fetuses within the womb. For many years, the uterus was assumed to be a dark environment, limited only to illumination under intense radiation. Recent research, however, shows that the human fetus exhibits brain activity when presented with visual stimuli and displays a preference for face-like stimuli presented via laser diode application to the maternal abdominal exterior. Despite growing evidence to support the notion of a visually engaged fetus during gestation, there has been minimal research undertaken to determine the extent to which the human uterus is illuminated by external light sources. Beyond aiding with experimental research in fetal vision, an understanding of uterine illumination begins to reveal the impact of varying environmental conditions on the fetal visual experience, with direct relevance to ongoing research across fields such as fetal vision, photoacoustics, and ectogenesis. This thesis outlines a mathematical model developed for the purposes of simulating the propagation of light sources through maternal tissue to the human fetus, with applications exploring the effect of adipose on transdermal monochromatic stimuli, the degree of uterine illumination imposed by natural light, and an extension to the illumination of a full maternal abdomen via a model that can account for curvature, varying tissue layer thicknesses, and the temporal aspects of pregnancy.