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Modern IVF treatments now achieve a 68.2% cumulative live birth rate over three cycles while maintaining a multiple birth rate of just 2.9%, according to research presented at the 42nd Annual Meeting of the European Society of Human Reproduction and Embryology (ESHRE). This represents a significant improvement over historical methods that often resulted in multiple pregnancies exceeding 20%.
How have IVF success rates changed over time?
Recent data shows a clear upward trend in IVF success rates alongside a sharp decline in high-risk multiple births. Researchers analyzed outcomes from 18,396 women undergoing their first IVF cycle between January 2012 and December 2021 across seven Australian fertility clinics. The study, which included follow-up through December 2023, found that modern clinical practices have effectively decoupled high success rates from the necessity of multiple embryo transfers.
The findings mark a notable shift when compared to historical data. Earlier studies, conducted before widespread adoption of modern laboratory techniques, reported three-cycle cumulative live birth rates between 53% and 59%. During those earlier periods, multiple pregnancy rates often exceeded 20%. In contrast, the current study reported a 68.2% cumulative live birth rate using optimal per-protocol analysis and a multiple birth rate of only 2.9%.
The researchers suggest these improved outcomes stem from several specific technological advancements:
- Blastocyst culture: Growing embryos to day 5 or 6.
- Embryo vitrification: Using rapid freezing techniques to improve survival rates.
- Freeze-all strategies: Transferring frozen embryos at a later date rather than during the initial stimulation cycle.
- Optimized protocols: Refined frozen embryo transfer (FET) procedures.
The proportion of fertilized eggs that successfully develop into usable blastocysts increased from 48.3% between 2012–2015 to 57.6% between 2017–2021, according to the study data.
Why is single embryo transfer becoming the standard?
For years, clinicians often transferred multiple embryos to increase the likelihood of pregnancy. However, Dr. Dean Morbeck, the study’s lead author, says this data challenges the assumption that transferring multiple embryos is required to maximize success. He noted that while transferring two embryos once increased pregnancy chances, it frequently led to twin pregnancy rates approaching 30%.
“What our data show is that this trade-off has largely disappeared,” Dr. Morbeck explained. He noted that across the 18,000+ women studied, clinicians achieved strong cumulative live birth rates while using single embryo transfer (SET) in 95.3% of cases, all while keeping the twin birth rate under 3%.
This shift is largely due to the evolution of laboratory environments. Dr. Morbeck stated that blastocyst culture has moved from being an exception to becoming the default. This transition drove improvements in IVF laboratories, including the use of purpose-built incubators, reduced oxygen conditions, and minimized disruption to embryos during the culture process.
How does maternal age impact IVF success?
While overall success rates are rising, the study confirms that age remains a critical factor in determining the probability of a live birth. The researchers found that success rates vary substantially depending on the age of the woman at the time of treatment.
The optimal cumulative live birth rates observed in the study were as follows:
| Age Group | Cumulative Live Birth Rate |
|---|---|
| Under 35 | 84.5% |
| 35–37 | 74.4% |
| 38–40 | 57.7% |
| 41–42 | 30.1% |
Is preimplantation genetic testing (PGT-A) always required?
The study also provides insight into the necessity of routine preimplantation genetic testing for aneuploidy (PGT-A), a process
