Cumulative live birth rates in a freeze-all or fresh transfer strategy after one ART cycle in ovulatory women

RESEARCH QUESTION: Are cumulative live birth rates similar following a freeze-all strategy compared with a fresh transfer strategy including all subsequent vitrified-warmed cycles from the same oocyte retrieval?

DESIGN: The study related to the secondary outcome in a multicentre randomized controlled trial including 460 women allocated in a 1:1 ratio to: (i) a freeze-all strategy including a gonadotrophin-releasing hormone agonist trigger and single vitrified-warmed blastocyst transfer in a subsequent modified-natural frozen-thawed embryo transfer (FET) cycle; or (ii) a fresh transfer strategy with a human chorionic gonadotrophin trigger and single blastocyst in the fresh cycle. Women were recruited over a 2-year period from May 2016 to September 2018. The minimum follow-up time from the start of ovarian stimulation was 2 years.

RESULTS: Baseline and treatment-related characteristics were similar between the two groups, and an equal number of participants had an additional FET following the initial fresh or frozen transfer in the two groups. Combining all FET from the included oocyte retrievals, the cumulative live birth rate was 42.6% (95/223) in the freeze-all group versus 41.7% (96/230) in the fresh strategy group (risk ratio 1.0, 95% CI 0.87-1.19; P = 0.93). The median time (interquartile range) to the first pregnancy was 106.0 (80.5-156.5) versus 29.0 (27.0-113.5) days in the freeze-all and fresh transfer group, respectively. The total number of deliveries from all subsequent FET cycles was similar between the freeze-all strategy and fresh transfer strategy group: 15.2% (34/223) versus 12.6% (29/230), respectively (P = 0.5).

CONCLUSIONS: When comparing a freeze-all strategy with a fresh transfer strategy in a randomized controlled trial setting, no significant difference was found in the cumulative live birth rates between the two strategies.