Synonyms for Impregnation (same or very similar meaning)
WordNet sense 1 (the process of totally saturating something with a substance):
saturationWordNet sense 2 (creation by the physical union of male and female gametes; of sperm and ova in an animal or pollen and ovule in a plant):
fecundation, fertilization, fertilisationFrom the ODE community, based on WordNetadd/edit