STUDY QUESTION: Do IVF outcomes differ in patients over the age of 40 using donor oocytes? SUMMARY ANSWER: Even with the use of donor oocytes, maternal age appears to have an impact on live birth (LB) rate and perinatal outcomes. WHAT IS KNOWN ALREADY: Maternal age has a significant impact on the outcome of IVF, mainly attributed to age-related oocyte chromosomal factors. STUDY DESIGN, SIZE, DURATION: This was a retrospective cohort study between 1 January 2015 and 31 December 2021. PARTICIPANTS/MATERIALS, SETTING, METHODS: This study included all patients who had a single embryo transfer cycle using donor oocytes during the study period. The study was conducted at a single university-affiliated fertility center. Data on BMI, paternal age, and type of cycle (natural vs programmed) were evaluated in relation to miscarriages and LBs when comparing age groups of 40-44, 45-49, and ≥50. Generalized estimating equation (GEE) models with logit functions were used to control for confounding variables. MAIN RESULTS AND THE ROLE OF CHANCE: A total of 1660 single embryo transfer cycles using donor oocytes in patients ≥40 years were performed during the study period. Of these, 969 were in patients aged 40-44, 607 in patients 45-49, and 84 in patients ≥50 years of age. The presence of an LB was significantly lower in patients 45-49 compared to those 40-44 (P = 0.023). The LB rate remained lower in patients >
50 but was not statistically significant. This relationship persisted after adjusting for BMI, paternal age, cycle type, and type of oocyte donor (fresh vs frozen oocyte donor) (P = 0.016). Moreover, the birthweight was lower in the older age groups (45-49 and ≥50) compared to the reference group of patients aged 40-44 (P = 0.004). LIMITATIONS, REASONS FOR CAUTION: The presence of an LB was lower in patients aged 45-49 and ≥50 compared to 40-44
however, this finding was not statistically significant for the ≥50 age group, likely due to the smaller sample size compared to the other two age groups. The use of preimplantation genetic testing for aneuploidy (PGT-A) was not included since only a minority of patients using donor oocytes underwent PGT-A. The inclusion of both fresh and frozen donor oocytes may also be deemed a limitation, as some studies have indicated better outcomes from fresh compared to frozen donor oocytes. WIDER IMPLICATIONS OF THE FINDINGS: Maternal age, beyond its relation to oocyte quality, was shown to affect the achievement of an LB. This is an important finding to include in patient counseling, particularly for those proceeding with donor oocytes. STUDY FUNDING/COMPETING INTEREST(S): No authors report conflicts of interest or disclosures. There was no study funding. TRIAL REGISTRATION NUMBER: N/A.