RESUMO
In some IVF cycles, no fresh embryo transfer in the stimulated cycle is advisable. The cryopreservation of zygotes and the transfer of blastocysts in a cryo-embryo transfer is an option to circumvent an inadequate uterine environment due to risk of ovarian hyperstimulation syndrome, inappropriate endometrium build up, endometrial polyps or uterine myomas. For this strategy, highly secure and safe cryopreservation protocols are advisable. This study describes a protocol for aseptic vitrification of zygotes that results in high survival rates and minimizes the potential risk of contamination in liquid nitrogen during cooling and long-term storage. In mouse zygotes, there was no difference in efficiency as compared with a conventional open vitrification system. In IVF patients, aseptically vitrified zygotes showed no difference in blastocyst formation rate as compared with sibling zygotes kept in fresh culture. A clinical study comprising 173 cryo-cycles with a transfer of blastocysts originating from vitrified zygotes showed an ongoing pregnancy rate of 40.9%. The live birth rate per patient was 36.8%. A combination of good clinical results and increased safety conditions due to aseptic vitrification encourages the use of cryo-embryo transfer for patients with a suboptimal uterine environment in a fresh cycle. In stimulated IVF cycles, high doses of hormones are given to stimulate multifollicular growth. One drawback of the hormonal substitution is that the uterine environment is not at the same time optimally prepared for embryo implantation. A solution, which is increasingly under discussion, is to cryopreserve the embryos obtained in the stimulated cycle and to transfer them back into the optimal uterine environment in a subsequent cryo-cycle. This procedure requires highly secure and safe cryopreservation protocols in order to ensure benefits for both pregnancy and birth rates. We have established a protocol for the vitrification of zygote-stage embryos in aseptic devices, which minimize the potential risk of contamination during cooling and storage. The vitrified zygotes showed the same blastocyst development as compared with sibling zygotes in fresh culture. A clinical study comprising 173 cryo-cycles with transfer of blastocysts originating from vitrified zygotes shows an ongoing pregnancy rate of 40.9%. The live birth rate per patient was 36.8%. A combination of good clinical results and increased safety conditions due to aseptic vitrification conditions contributes to a change in transfer strategy and encourages us to increase the cryo-embryo transfer rate for an optimal uterine environment.
Assuntos
Criopreservação/métodos , Transferência Embrionária , Infertilidade Feminina/terapia , Doenças Uterinas/etiologia , Vitrificação , Zigoto , Adulto , Animais , Bélgica/epidemiologia , Coeficiente de Natalidade , Criopreservação/instrumentação , Ectogênese , Feminino , Humanos , Infertilidade Feminina/complicações , Camundongos , Camundongos Endogâmicos , Síndrome de Hiperestimulação Ovariana/epidemiologia , Síndrome de Hiperestimulação Ovariana/fisiopatologia , Gravidez , Taxa de Gravidez , Distribuição Aleatória , Estudos Retrospectivos , Risco , Doenças Uterinas/complicações , Doenças Uterinas/epidemiologia , Adulto JovemRESUMO
Spermatozoa selection at high magnification before intracytoplasmic sperm injection seems to be positively associated with pregnancy rates after day 3 embryo transfers. The aim was to demonstrate an association between the presence of vacuoles in sperm nuclei and the competence of embryos to develop to day 5. Grading of spermatozoa at x 6000-x 12,500 magnification: grade I, no vacuoles; grade II,
Assuntos
Blastocisto/citologia , Desenvolvimento Embrionário , Espermatozoides/ultraestrutura , Adulto , Núcleo Celular/ultraestrutura , Transferência Embrionária , Feminino , Humanos , Recém-Nascido , Infertilidade Masculina/patologia , Infertilidade Masculina/terapia , Masculino , Gravidez , Resultado da Gravidez , Injeções de Esperma Intracitoplásmicas/métodos , Vacúolos/ultraestruturaRESUMO
To determine the best day for the selection and transfer of a single embryo, a prospective, randomized study was undertaken that compared the ongoing pregnancy rate (PR) after single embryo transfer (SET) on day 3 with that after single blastocyst transfer (SBT) on day 5. Our results show an overall significantly higher PR after SBT (32.8%) compared with SET (23.2%), and a PR of 40.8% after SBT versus 25.6% after excellent-quality embryos became available.