News | Fresh Embryo Transfer May Improve IVF Success in Women With a Poor Prognosis
A new Chinese study found that fresh embryo transfer may be more suitable than frozen embryo transfer for women with a poor IVF prognosis. Published today in The BMJ, the findings suggest that freezing all embryos may not routinely be the best option for women with lower chances of IVF success.
Background and findings
IVF has transformed infertility treatment. In the common "freeze-all" strategy, all suitable embryos are frozen before transfer to avoid an excessive response to ovarian stimulation for fresh egg retrieval. Most freeze-all research has focused on women with a good IVF prognosis and found similar cumulative live-birth rates with fresh and frozen transfers. Evidence in women with a poor prognosis has remained limited.
To address this gap, researchers at nine fertility centers in China randomized 838 women aged 33 to 34 with a poor IVF prognosis and compared live-birth rates after fresh and frozen embryo transfer. From December 2021 to May 2023, participants were assigned to frozen- or fresh-embryo groups, and live births after the first transfer were tracked through April 2024.
Results
The live-birth rate was significantly higher after fresh transfer. Among 419 women in the frozen-transfer group, 132 (32%) conceived and gave birth, compared with 168 of 419 women (40%) in the fresh-transfer group.
Pregnancy rates were also higher with fresh transfer: 47% (197/419) versus 39% (164/419). After subsequent transfers, cumulative live-birth rates were 51% (215/419) in the fresh group and 44% (185/419) in the frozen group.
No significant differences were found in birth weight, obstetric complications, or neonatal disease risk.
Limitations and future directions
The researchers acknowledged limitations, including differences in the number and developmental stage of transferred embryos that may partly explain the live-birth results.
They nevertheless said the study complements earlier trials in women with normal or good prognoses and clarifies the benefits and risks of freeze-all and fresh-transfer strategies. They concluded: "Compared with frozen embryo transfer, fresh embryo transfer may offer a better live-birth rate for women with a poor prognosis."
Future research should determine the appropriate number and developmental stage of embryos for achieving the best singleton-pregnancy outcomes in women with a poor prognosis.
Conclusion and clinical significance
The study offers useful guidance for women with a poor IVF prognosis, particularly regarding the potential advantages of fresh transfer. Dutch experts noted in an accompanying editorial that potential bias may affect interpretation. They stressed that any benefit must be weighed against disadvantages at fertility centers using advanced IVF technology and multiple frozen-embryo cycles.
Accurate evaluation of these methods is essential to improving outcomes for this population.
News | Fresh Embryo Transfer May Improve IVF Success in Women With a Poor Prognosis
News | Fresh Embryo Transfer May Improve IVF Success in Women With a Poor Prognosis
A new Chinese study found that fresh embryo transfer may be more suitable than frozen embryo transfer for women with a poor IVF prognosis. Published today in The BMJ, the findings suggest that freezing all embryos may not routinely be the best option for women with lower chances of IVF success.
Background and findings
IVF has transformed infertility treatment. In the common "freeze-all" strategy, all suitable embryos are frozen before transfer to avoid an excessive response to ovarian stimulation for fresh egg retrieval. Most freeze-all research has focused on women with a good IVF prognosis and found similar cumulative live-birth rates with fresh and frozen transfers. Evidence in women with a poor prognosis has remained limited.
To address this gap, researchers at nine fertility centers in China randomized 838 women aged 33 to 34 with a poor IVF prognosis and compared live-birth rates after fresh and frozen embryo transfer. From December 2021 to May 2023, participants were assigned to frozen- or fresh-embryo groups, and live births after the first transfer were tracked through April 2024.
Results
The live-birth rate was significantly higher after fresh transfer. Among 419 women in the frozen-transfer group, 132 (32%) conceived and gave birth, compared with 168 of 419 women (40%) in the fresh-transfer group.
Pregnancy rates were also higher with fresh transfer: 47% (197/419) versus 39% (164/419). After subsequent transfers, cumulative live-birth rates were 51% (215/419) in the fresh group and 44% (185/419) in the frozen group.
No significant differences were found in birth weight, obstetric complications, or neonatal disease risk.
Limitations and future directions
The researchers acknowledged limitations, including differences in the number and developmental stage of transferred embryos that may partly explain the live-birth results.
They nevertheless said the study complements earlier trials in women with normal or good prognoses and clarifies the benefits and risks of freeze-all and fresh-transfer strategies. They concluded: "Compared with frozen embryo transfer, fresh embryo transfer may offer a better live-birth rate for women with a poor prognosis."
Future research should determine the appropriate number and developmental stage of embryos for achieving the best singleton-pregnancy outcomes in women with a poor prognosis.
Conclusion and clinical significance
The study offers useful guidance for women with a poor IVF prognosis, particularly regarding the potential advantages of fresh transfer. Dutch experts noted in an accompanying editorial that potential bias may affect interpretation. They stressed that any benefit must be weighed against disadvantages at fertility centers using advanced IVF technology and multiple frozen-embryo cycles.
Accurate evaluation of these methods is essential to improving outcomes for this population.
Source:
Collected online