Purpose: Time-lapse monitoring allows for a flexible embryo evaluation and potentially provides new dynamic markers of embryo competence. Before introducing time-lapse monitoring in a clinical setting, the safety of the instrument must be properly documented. Accordingly, the aim of this study was to evaluate the safety of a commercially available time-lapse incubator.
Methods: In a two center, randomized, controlled, clinical trial 676 oocytes from 59 patients in their 2nd or third treatment cycle, age <38 years and ≥ 8 oocytes retrieved were cultured in the time-lapse incubator or in a conventional incubator. The primary outcome was proportion of 4-cell embryos on day 2. Secondary outcomes were proportion of 7-8 cell embryos on day 3 and proportion of blastocysts on day 5. Implantation pregnancy rates were registered based on presence of fetal heart activity visualized by ultrasound 8 weeks after embryo transfer.
Results: No significant difference was found between the time-lapse incubator (TLI) and conventional incubator (COI) in proportion of 4-cell embryos on day 2 irrespective of whether data was analyzed according to ITT (RR(TLI/COI): 0.81 (0.65; 1.02)) or PP (RR(TLI/COI): 0.80 (0.63; 1.01)). Nor were any significant differences detected in the secondary endpoints; i.e. proportion of 7-8-cell embryos on day three ITT (RR(TLI/COI): 0.96 (0.73; 1.26)); PP (RR(TLI/COI): 0.95 (0.72; 1.26)) and proportion of blastocysts on day five ITT (RR(TLI/COI): 1.09 (0.84; 1.41)); PP (RR(TLI/COI): 1.09 (0.83: 1.41)). We found no differences in clinical pregnancy rate or implantation rate.
Conclusion: Culture in the time-lapse incubator supports embryonic development equally to a conventional incubator.