Final answer:
DeLancey's Level 1 Vaginal Support refers to the suspension of the vaginal apex by the cardinal and uterosacral ligaments, and defects in this support level can cause prolapse of upper vaginal and uterine structures.
Step-by-step explanation:
DeLancey's Levels of Vaginal Support are a medical classification system used to describe the support structures of the vaginal canal and the mechanisms that lead to pelvic organ prolapse. Level 1 support is the highest and functions through the suspension of the vaginal apex by the cardinal and uterosacral ligament complexes. Any defects at this level can lead to prolapse of the upper vagina and uterus (or apex of the vagina if the uterus has been removed).