Effect of early rescue ICSI in multiple cycles of couples with successful fertilization in the initial cycle of conventional IVF.

backgroundTotal fertilization failure (TFF) or near TFF may lead to cycle cancellation, which is a highly frustrating experience for patients, especially those who have undergone multiple attempts. Early rescue intracytoplasmic sperm injection (R-ICSI) has been shown to yield promising clinical results. In this research, we aimed to investigate whether embryo development and clinical outcomes would be affected in subsequent R-ICSI cycles for couples with successful fertilization in the initial cycle of conventional in vitro fertilization (C-IVF).

methodsThis retrospective cohort study was conducted from January 2014 to December 2023, including 72 couples who demonstrated normal or nearly normal fertilization potential (≥ 40% 2PN rate) in previous C-IVF cycles but subsequently underwent TFF or near TFF in repeated C-IVF cycles. Only the first embryo transfer was analyzed for comparison in each treatment cycle. A comparative analysis was performed between embryo development parameters and clinical outcomes following early R-ICSI versus previous C-IVF.

resultsOur data indicated that couples undergoing their first C-IVF cycle demonstrated a significantly higher early R-ICSI rate compared to those in their second or subsequent treatment cycles (4.00 versus 1.09%; p < 0.001 and 4.00 versus 0.68%; p < 0.001). For couples undergoing their second cycles, the 2PN rate following early R-ICSI was comparable to that achieved with previous C-IVF (55.42 versus 55.27%; p = 0.929). The D3 available embryo rate was significantly higher following early R-ICSI compared to conventional C-IVF (79.34 versus 68.71%; p = 0.002). Early R-ICSI demonstrated significantly superior clinical outcomes compared to previous C-IVF, with higher pregnancy (58.06 versus 24.13%; p < 0.001), clinical pregnancy (48.39 versus 20.69%; p = 0.002), ongoing pregnancy (38.71 versus 8.62%; p < 0.001), and live birth rates (38.71 versus 5.17%; p < 0.001). For couples undergoing their multiple cycles (≥ 3), early R-ICSI showed significantly lower 2PN (44.44 versus 62.18%; p = 0.006) and D3 available embryo (52.27 versus 70.10%; p = 0.040) rates compared to previous C-IVF. Early R-ICSI demonstrated no statistically significant differences in clinical outcomes compared to previous C-IVF, including pregnancy (44.44 versus 28.57%; p = 0.398), clinical pregnancy (44.44 versus 14.29%; p = 0.074), ongoing pregnancy (33.33 versus 9.52%; p = 0.109), and live birth (33.33 versus 9.52%; p = 0.109) rates.

conclusionFor patients undergoing two or more IVF treatment cycles, fertilization failure is not a predictor of poor treatment outcomes and early R-ICSI can still lead to a favorable outcome.