EFFECT OF AGING ON THE FEMALE REPRODUCTIVE-SYSTEM - EVIDENCE FOR A ROLE OF UTERINE SENESCENCE IN THE DECLINE IN FEMALE FECUNDITY

Objective: To determine the effects of age on reproductive performance of women using oocyte donation as an in vivo model. Setting: Oocyte donation and IVF programs at the Institute Valenciano de Infertilidad. Patients: Seventy-six women undergoing 90 cycles of ovum donation, who were recipients of 36 donors undergoing IVF, and 9 fertile women. Design: Prospective longitudinal study: [1] recipients underwent an artificial cycle to demonstrate adequate response of the endometrium to exogenous steroids; [2] oocytes from the same cohort of follicles were distributed randomly into recipients younger and older than 40 years; and [3] pregnancies were followed during the first trimester. Main Outcome Measures: Endometrial histology, fertilization, embryo quality, pregnancy, implantation, and abortion rates in both groups of recipients. Serum E(2), P and beta-hCG levels during initial pregnancy. Results: Similar implantation rates but significantly higher abortion rates were detected in women > 40 years despite an appropriate action of P on the endometrium and the transfer of embryos in similar number and quality. The secretion of E(2) and P by the placenta started earlier in pregnancies included in the group < 40 years. Conclusions: Age increases pregnancy losses in ovum donation patients after implantation is completed. This is accompanied by a retardation of steroid synthesis and suggests that the mechanism(s) responsible for placenta formation and functioning in the uterus is affected by age. Thus, uterine aging also is a factor influencing the poor reproductive performance of women with advancing age.