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 d onation 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. Des ign: Prospective longitudinal study: [1] recipients underwent an artif icial cycle to demonstrate adequate response of the endometrium to exo genous steroids; [2] oocytes from the same cohort of follicles were di stributed randomly into recipients younger and older than 40 years; an d [3] pregnancies were followed during the first trimester. Main Outco me Measures: Endometrial histology, fertilization, embryo quality, pre gnancy, 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 wer e detected in women > 40 years despite an appropriate action of P on t he endometrium and the transfer of embryos in similar number and quali ty. The secretion of E(2) and P by the placenta started earlier in pre gnancies included in the group < 40 years. Conclusions: Age increases pregnancy losses in ovum donation patients after implantation is compl eted. This is accompanied by a retardation of steroid synthesis and su ggests that the mechanism(s) responsible for placenta formation and fu nctioning in the uterus is affected by age. Thus, uterine aging also i s a factor influencing the poor reproductive performance of women with advancing age.