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Cumulative live birth rates following a 'freeze-all' strategy: a population-based study
1Sydney Medical School, Faculty of Medicine and Health, University of Sydney, Sydney NSW, Australia.
Human Reproduction Open
|March 22, 2019
Summary
The freeze-all strategy for embryo transfer showed similar live birth rates to fresh transfer in high responders but was less effective for normal and suboptimal responders. This suggests personalized approaches are needed for assisted reproductive technology (ART).
Area of Science:
- Reproductive Medicine
- Assisted Reproductive Technology (ART)
- Embryology
Background:
- Frozen-thawed embryo transfer is linked to reduced adverse obstetric and perinatal outcomes compared to fresh embryo transfer.
- The universal application of the 'freeze-all' strategy in ART remains under investigation.
Purpose of the Study:
- To compare the cumulative live birth rate between 'freeze-all' and 'fresh-transfer' strategies in women undergoing ART.
- To determine if the 'freeze-all' strategy offers benefits across different patient response levels.
Main Methods:
- A population-based retrospective cohort study involving 14,331 women undergoing their first stimulated ART cycle.
- Women were categorized into 'freeze-all' (n=1028) or 'fresh-transfer' (n=13,303) groups.
- A discrete-time survival model analyzed cumulative live birth rates.
Main Results:
- For high responders (>15 oocytes), cumulative live birth rates were similar between 'freeze-all' (56.8%) and 'fresh-transfer' (56.2%) strategies.
- The 'freeze-all' strategy showed lower live birth rates in normal (33.2% vs. 46.3%) and suboptimal (<10 oocytes) responders (14.6% vs. 28.0%).
- A significant proportion of suboptimal and normal responders in the 'freeze-all' group did not return for embryo transfer.
Conclusions:
- The 'freeze-all' strategy may benefit high responders and those at risk of OHSS but is not universally advantageous.
- Clinicians should consider individual patient factors and the risk of treatment discontinuation when selecting an embryo transfer strategy.
- This study provides population-based evidence on the clinical efficacy of different embryo transfer strategies in ART.
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