High live birth rate among recipient couples who require a replacement lot of vitrified donor oocytes

To analyze characteristics and subsequent outcomes of patients who failed their first cycle using vitrified donor oocytes (no available blastocysts) and required a replacement lot to those who did not.

This was a retrospective cohort study at a multicenter assisted reproductive technology practice. Patients were included if no blastocysts were suitable for transfer after using a vitrified donor oocyte lot from a large, national donor oocyte consortium between 2018 and 2022. Patients were excluded if they opted out of using a replacement lot for the exposure group, or if they had uterine factor and/or severe male factor infertility. They were compared to patients who did not require a replacement lot during the same time period for the primary outcome of live birth and secondary outcomes of fertilization, blastulation, and clinical pregnancy.

There were a total of 70 recipient couples who used a replacement lot compared to 1012 recipient couples who did not (controls). There were similar baseline characteristics in both cohorts, with most couples using partner sperm and opting out of preimplantation genetic testing for aneuploidy (PGT-A). From patients using replacement lots, 41 (59%) achieved a clinical pregnancy with the immediate next cycle and 33 (47%) with a live birth. Twenty-nine (71% of pregnant couples) of these patients had a live birth with a new oocyte donor and the same sperm source. Four (10% of pregnant couples) had a live birth with a new oocyte donor and a new sperm source using donor sperm (with the partner as the prior sperm source). Twenty-nine couples did not get pregnant using a new oocyte donor and the primary lot sperm source. When compared to the control cohort, the patients who did not achieve a live birth with a replacement lot were older females with older male partners and had lower blastulation. However, after controlling for age, BMI, and number of embryos transferred, cycle outcomes were similar with no statistically significant difference in primary outcome of live birth (52% vs 53% controls, aRR 0.9 95% CI 0.8-1.1), or fertilization, blastulation, or clinical pregnancy. This was consistent in PGT-A-only cycles and non-PGT-A cycles.

This study found a high probability of live birth from a second attempt using a replacement oocyte lot. These data can reassure physicians and donor oocyte recipients to persevere in treatment following an unsuccessful oocyte lot outcome.