Characteristics of uterine aging

Abstract Uterine aging is in part responsible for a decline in fecundity which begins in middle age in most mammals. Characteristics of uteri from a variety of animals in middle age and old age are reviewed and the factors which may be responsible for this decline discussed. These include age‐related changes in the hypothalamus, pituitary, and ovaries; loss of number or function of steroid hormone receptors; morphological changes in the uterine epithelium; the accumulation of collagen fibrils in the uterine stroma; and loss or impairment of the decidual response. The ultra‐structural morphology of uterine epithelial, stromal, and decidual tissue from 4 month old and 18 month old Fischer 344 rats is presented and compared. © 1993 Wiley‐Liss, Inc.