A NEW study suggests that fresh embryo transfer may offer a better chance of live birth for women with a low prognosis for in vitro fertilisation (IVF) treatment compared to a freeze-all strategy. The findings challenge the growing trend of freezing embryos before transfer, particularly for patients with limited ovarian reserve.
Conducted across nine academic fertility centres in China, the study involved 838 women classified as having a low prognosis for IVF, either due to retrieving nine or fewer oocytes or exhibiting poor ovarian reserve. Participants were randomly assigned to either undergo fresh embryo transfer immediately after oocyte retrieval or to freeze all embryos for transfer at a later date.
The results revealed that the live birth rate for the fresh embryo transfer group was 40%, significantly higher than the 32% observed in the frozen embryo transfer group. The cumulative live birth rate, accounting for all embryo transfers within a year of randomisation, was also higher for fresh transfers (51% vs. 44%). Clinical pregnancy rates followed a similar pattern, with 47% of fresh transfers resulting in pregnancy compared to 39% for frozen transfers.
Interestingly, the study found no significant differences between the two groups in terms of birth weight, maternal complications, or neonatal morbidities, suggesting that the benefits of fresh embryo transfer in this patient population do not come at the cost of increased risks for mothers or babies.
“The findings suggest that for women with a low prognosis, fresh embryo transfer may maximize the chances of achieving a live birth,” said Zi-Jiang Chen, the study’s senior author. The study also calls for more research into strategies that delay fresh transfers, such as back-to-back embryo accumulation cycles and preimplantation genetic testing for aneuploidy.
Aleksandra Zurowska, EMJ
Reference
Wei D et al. Frozen versus fresh embryo transfer in women with low prognosis for in vitro fertilisation treatment: pragmatic, multicentre, randomised controlled trial. BMJ. 2025;388:e081474.
