The effectiveness of vitrified zygote accumulation for managing the extremely diminished ovarian reserve in infertile women: a retrospective cohort study

Abstract Background Accumulated vitrified embryos are stored for later thawed transfer to deal with poor responders. However, the cost and outcome of vitrified zygotes have yet to be studied. Our study aimed to investigate the effectiveness of the vitrified zygote accumulation method in diminished ovarian reserve patients. Methods This retrospective study included 122 diminished ovarian reserve patients who met the Poseidon classification groups 3 and 4 from June 1, 2019, to December 31, 2022. The patients underwent controlled ovarian stimulation and embryo transfer using accumulated vitrified zygotes. The clinical pregnancy rate and live birth rate per embryo transfer and stimulation cycle are evaluated. Results Two hundred seventy-eight IVF/ICSI cycles in one hundred twenty-two females treated at our institution were divided into two groups, according to age < 40 years (n = 51) and ≥ 40 years (n = 71). The younger group had significantly more favorable outcomes than the older group only in live birth rates per cycle (12.6% vs. 4%, p = 0.029) and per transfer (24.1% vs. 9.9%, p = 0.027). However, the older group had more embryos per transfer (2.4 ± 0.9 vs. 2.0 ± 0.8, p = 0.014). There were no differences between the number of stimulation cycles per patient, the number of oocytes and mature oocytes retrieved, the number of transfer cycles per patient, the cost per patient, or transfer. We set a model mimicking the cost of fresh embryos. The zygote accumulation strategy costs were higher per patient and per cycle than those of the fresh embryo transfer model. Conclusions In diminished ovarian reserve women undergoing IVF/ICSI treatment, younger women had significantly better live birth rates than the older women applying the vitrified zygote accumulation strategy, even though the older group had a higher number of embryos per transfer. However, the zygote accumulation strategy benefits older women more than fresh embryo transfer. The strategy might cost more but decrease the anxiety and stress.