Noninvasive embryo evaluation and selection by time-lapse monitoring vs. conventional morphologic assessment in women undergoing in vitro fertilizati on/intracytoplasmic sperm injection: a single-center randomized controlled study

Objective: To determine whether time-lapse monitoring (TLM) for cleavage-stage embryo selection improves reproductive outcomes in comparison with conventional morphological assessment (CMA) selection. Design: Prospective randomized controlled trial. Setting: Single academic center. Patients: We randomly assigned 139 women who were undergoing their first in vitro fertilization or intracytoplasmic sperm injection cycle to undergo either fresh embryo transfer or first frozen embryo transfer (FET). Only 1 cleavage-stage embryo was transferred to each participant. Interventions: The patients were randomly assigned to either the CMA or the TLM group. In the CMA group, day 2 and day 3 embryos were observed. A good-quality cleavage-stage embryo was selected for transfer or freezing in both groups. Main Outcome Measures: The primary and secondary outcomes were the clinical pregnancy rate (CPR) and the live birth rate (LBR), respectively, after the first embryo transfer (fresh embryo transfer or FET). Results: The CPR and LBR were significantly lower in the TLM group than in the CMA group (CPR: 49.18% vs. 70.42%; relative risk, 0.70; 95% confidence interval [CI], 0.52-0.94; LBR: 45.90% vs. 64.79%; relative risk, 0.71; 95% CI, 0.51-0.98). The CPR with fresh embryo transfer or FET did not significantly differ between the TLM and the CMA groups (fresh embryo transfer: 44.44% vs. 70.0%, relative risk, 0.63, 95% CI, 0.39-1.03; FET: 52.94% vs. 70.73%, relative risk, 0.75, 95% CI, 0.52-1.09). There was a significant difference in the LBR with fresh embryo transfer between the TLM and the CMA groups (40.74% vs. 66.67%; relative risk, 0.61; 95% CI, 0.36-1.03). The LBRs with FET were similar in the TLM and the CMA groups (50.0% vs. 63.41%; relative risk, 0.79; 95% CI, 0.52-1.19). The rates of early spontaneous abortion and ectopic pregnancy did not differ between the TLM and the CMA groups. Conclusions: Elective single cleavage-stage embryo transfer with TLM-based selection did not have any advantages over CMA when day 2 and day 3 embryo morphology was combined in young women with a good ovarian reserve. Because of these results, we conclude that TLM remains an investigational procedure for in vitro fertilization practice. Clinical trial registration number: ChiCTR1900021981. ((C) 2022 by American Society for Reproductive Medicine.)

Automated summary

This prospective randomized controlled trial aimed to compare the effectiveness of time-lapse monitoring (TLM) and conventional morphological assessment (CMA) for embryo selection. The results showed that the clinical pregnancy rate (CPR) and live birth rate (LBR) were significantly lower in the TLM group compared to the CMA group. However, there was no significant difference in CPR between the TLM and CMA groups for fresh embryo transfer or FET.