Age-related decline in female fertility is not due to diminished capacity of the uterus to sustain embryo implantation.

OBJECTIVE: To evaluate the contribution of the uterus to age-related reproductive failure in women.

PATIENTS: Thirty-eight ovum donors (30.2 +/- 4.9 years [mean +/- SD]) donating oocytes throughout 102 ovum donations. Fifty-one cycles were documented in "younger" recipients (35.8 +/- 3.1 years) and 51 in "older" recipients (44.0 +/- 3.1 years). The study was prospectively designed; same-cohort oocytes obtained from one young donor during a specific cycle were evenly distributed between "young" and "old" ovum recipients. Use of oocytes from a single source and a unique ovulatory cohort provides strict control over oocyte quality. Uterine age is varied by design, according to the age of the recipient at the time of ET. The role of the aging uterus in the decline of female fertility can be thus isolated and scrutinized.

RESULTS: No significant (NS) difference in the number of ova received (7.9 +/- 3.4 versus 7.0 +/- 3.5), ova fertilized (4.4 +/- 1.5 versus 4.5 +/- 2.3), or embryos transferred (4.1 +/- 1.5 versus 4.1 +/- 1.6) was observed between the < 40 and > or = 40 recipient age groups. A total of 23 pregnancies occurred among the 102 ETs (22.6%). Eleven clinical pregnancies (21.6%) resulting in 10 deliveries were observed in the < 40 recipient age group, and 12 clinical pregnancies (23.5%) leading to 10 deliveries occurred in the > or = 40 recipient age group (NS). The pregnancy loss rates were 9.1% (1 of 11) and 16.7% (2 of 12) for the two recipient age groups, respectively, (NS).

CONCLUSION: The capacity to conceive and to gestate a conception to term when oocyte quality is controlled appears to be independent of uterine aging through the fifth decade of life.