Fresh versus frozen embryo transfers in assisted reproduction

Zaat, Tjitske; Zagers, Miriam S.; Mol, Femke; Goddijn, Mariëtte; Wely, Madelon van; Mastenbroek, Sebastiaan

doi:10.1002/14651858.cd011184.pub3

Cited by 75 publications

(81 citation statements)

References 78 publications

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“…This finding agrees with two recent systematic reviews, which did not demonstrate the superiority of the freezeall strategy for patients with normal response to ovarian stimulation. (12,13) Our analysis of the stage at which embryos were transferred indicated a clinically relevant and statistically significant higher pregnancy rate, when thawed blastocysts were transferred in freeze-all cycles. Previous studies evolving high responder patients indicated extended culture and blastocyst freezing were conducive to improved results with the freezeall strategy, mainly after the widespread utilization of vitrification technique.…”

Section: Logistic Regression Analysismentioning

confidence: 91%

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Freeze-all policy for in vitro fertilization in women with normal response to ovarian stimulation

Duarte-Filho

Podgaec

2021

Einstein (São Paulo)

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Objective: To answer the question if the freeze-all strategy and subsequent frozen embryo transfer is preferable to fresh embryo transfer for patients with normal response to ovarian stimulation (4 to 15 oocytes recovered) during in vitro fertilization treatments. Methods: A retrospective cohort from two human reproduction centers between 2013 and 2017. A total of 471 frozen embryo transfers from freeze-all cycles, and 3,208 fresh transfers were included. Results: After propensity score matching adjustment for age and number of eggs, 467 freeze-all cycles and 934 fresh cycles were analyzed, revealing no statistically significant difference between groups in relation to clinical pregnancy rate (32.5% in the Freeze-all Group and 32.3% in the Fresh Group, p=0.936). For women aged 40 years and older, we observed a statistically significant higher clinical pregnancy rate when freeze-all strategy was used (29.3% in the Freeze-all Group and 19.8% in the Fresh Group, p=0.04). Conclusion: Freeze-all strategy was not superior to fresh transfer for all patients with normal response to ovarian stimulation. However, women aged 40 years and older could benefit from this strategy. This deserves further investigation in future research, preferable in a prospective randomized study.

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Section: Logistic Regression Analysismentioning

confidence: 91%

“…(9)(10)(11) Two recent meta-analyses found similar pregnancy rates between the two strategies for patients with normal response to ovulation stimulation, but there is much heterogeneity among the studies, and the evidence to support this strategy is still considered of low-quality. (12,13)…”

Section: ❚ Introductionmentioning

confidence: 99%

Freeze-all policy for in vitro fertilization in women with normal response to ovarian stimulation

Duarte-Filho

Podgaec

2021

Einstein (São Paulo)

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“…In humans, available data suggest that vitrification/warming is superior to slow freezing/thawing with respect to clinical outcomes and cryosurvival rates either for oocytes, cleavage-stage embryos and blastocysts (reviewed in [ 181 ]). The high results of vitrification, particularly at blastocyst stage, have made it possible to change clinical practices with differed embryo transfer (freeze-all strategy) to avoid ovarian hyperstimulation syndrome with identical to superior results [ 182 ]. In equine, vitrification has proven very successful for in vitro produced embryos that are smaller than in vivo embryos and is now widely used, even though these embryos can also be cryopreserved with the slow cooling method [ 183 , 184 ].…”

Section: Comparison Of Assisted Reproduction Techniques In Horses and Humansmentioning

confidence: 99%

The Mare: A Pertinent Model for Human Assisted Reproductive Technologies?

Benammar

Derisoud

Vialard

et al. 2021

Animals

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Although there are large differences between horses and humans for reproductive anatomy, follicular dynamics, mono-ovulation, and embryo development kinetics until the blastocyst stage are similar. In contrast to humans, however, horses are seasonal animals and do not have a menstrual cycle. Moreover, horse implantation takes place 30 days later than in humans. In terms of artificial reproduction techniques (ART), oocytes are generally matured in vitro in horses because ovarian stimulation remains inefficient. This allows the collection of oocytes without hormonal treatments. In humans, in vivo matured oocytes are collected after ovarian stimulation. Subsequently, only intra-cytoplasmic sperm injection (ICSI) is performed in horses to produce embryos, whereas both in vitro fertilization and ICSI are applied in humans. Embryos are transferred only as blastocysts in horses. In contrast, four cells to blastocyst stage embryos are transferred in humans. Embryo and oocyte cryopreservation has been mastered in humans, but not completely in horses. Finally, both species share infertility concerns due to ageing and obesity. Thus, reciprocal knowledge could be gained through the comparative study of ART and infertility treatments both in woman and mare, even though the horse could not be used as a single model for human ART.

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“…Nevertheless, some other studies comparing fresh and frozen embryo transfers were less conclusive as to the overall beneficial effect on embryo implantation in the whole population of infertile women. A Cochrane systematic review [11] found evidence showing seemingly no difference between the two strategies in cumulative live birth rate per woman. This appears to be due to the fact that some women can benefit from frozen embryo transfer more than others, depending on their response to ovarian stimulation.…”

Section: Background and State Of The Artmentioning

confidence: 99%

The Freeze-All Strategy Revisited: New Pieces to the Old Puzzle

Tesarik

2021

JGWH

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Fresh versus frozen embryo transfers in assisted reproduction

Cited by 75 publications

References 78 publications

Freeze-all policy for in vitro fertilization in women with normal response to ovarian stimulation

Freeze-all policy for in vitro fertilization in women with normal response to ovarian stimulation

The Mare: A Pertinent Model for Human Assisted Reproductive Technologies?

The Freeze-All Strategy Revisited: New Pieces to the Old Puzzle

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