Fresh embryo transfer could be the most effective option for women with a low likelihood of achieving a live birth through IVF.
Traditionally, embryo cryopreservation has been used to store surplus embryos following fresh embryo transfers, maximising the chances of a successful pregnancy through subsequent cycles. However, in recent years, a shift toward electively freezing all embryos followed by planned frozen embryo transfers has gained popularity. Previous research has shown similar success rates between fresh and frozen embryo transfer in women with a good or normal prognosis of a live birth through IVF (see BioNews 1059). However, a new study, published in the BMJ, suggests that the 'freeze-all strategy' may not be the best option for women with a low prognosis.
'Fresh embryo transfer may be a better choice for women with low prognosis for IVF in terms of live birth rate compared with frozen embryo transfer,' the study authors conclude. 'The treatment strategies that prevent fresh embryo transfers, such as accumulating embryos with back-to-back cycles or performing routine preimplantation genetic testing for aneuploidy, warrant further studies in women with a low prognosis.'
The trial took place across nine fertility centres in China, and included 838 women aged 33-34 with a low prognosis for a live birth through IVF treatment, defined as having a poor ovarian reserve or fewer than nine eggs retrieved. Participants were randomly assigned to either the frozen or fresh embryo transfer groups. The findings revealed that 32 percent of women in the frozen embryo transfer group had a live birth, compared to 40 percent in the fresh embryo transfer group.
In addition, the cumulative live birth rate (which accounts for all embryo transfers within one year of the initial treatment) was greater in the fresh embryo transfer group at 51 percent, compared to 44 percent in the frozen group. The frozen group also showed a lower twin birth rate, a lower clinical pregnancy rate, and a higher miscarriage rate. However, there were no significant differences in birth weights, the health of the babies, or pregnancy complications such as pre-eclampsia between the two groups. These findings challenge the growing reliance on the 'freeze-all strategy' for this group of women.
'How to optimally use the "precious" embryos to increase the chance of live birth in these patients is an important clinical question,' Daimin Wei, professor at Shandong University's reproductive medical centre, China, and the study’s lead author, told Euronews Health. 'For clinicians, it is suggested to individually choose the embryo transfer strategy based on ovarian response and patients' characteristics to optimise the IVF outcomes.'
The study had certain limitations that could have impacted the results, such as the lack of standardisation in the stimulation protocol, the number and stage of embryos used, and the preparation of the uterus before embryo transfer. The researchers note that further research is needed to determine the underlying mechanisms behind the results and 'to explore the optimal number and stage of embryos for fresh transfer in women with low prognosis for IVF to have a singleton pregnancy.'
Sources and References
-
Fresh embryo transfer may improve IVF success for women with low prognosis
-
Frozen versus fresh embryo transfer in women with low prognosis for in vitro fertilisation treatment: pragmatic, multicentre, randomised controlled trial
-
Fresh embryo transfers linked to higher birth rates in women struggling to conceive with IVF
-
Fresh embryo transfer may be better for women with low chance of IVF success
Leave a Reply
You must be logged in to post a comment.