OBJECTIVE The aim of this study was to investigate associations between the morphology score of blastocysts and blastocoele re-expansion speed after warming with clinical outcomes, which could assist in making correct and cost-effective decisions regarding the appropriate time to vitrify blastocysts and to transfer vitrified-warmed blastocysts. METHODS A total of 327 vitrified-warmed two-blas...

The study was to investigate the effects of oxygen concentration at different levels for culturing pre-compaction embryos on human embryo development competence. A total of 1254 oocytes from 92 patients treated with conventional in vitro fertilization (IVF) were harvested in this study. Oocytes were randomly assigned to the atmospheric (~20%) or low (~5%) oxygen concentration groups on the retr...

Appropriate selection of a single blastocyst for transfer decreases the risk of multiple gestations. By using a compact time-lapse microscope system placed inside a regular incubator, combined with a microwell embryo culture dish, the development of all the embryos from a patient was continuously monitored by obtaining images at 10 min intervals. The embryos were not moved during the time-lapse...

STUDY QUESTION What type of transferred embryo is associated with a lower rate of ectopic pregnancy? SUMMARY ANSWER The lowest risk of ectopic pregnancy was associated with the transfer of blastocyst, frozen and single embryo compared with cleavage stage, fresh and multiple embryos. WHAT IS KNOWN ALREADY Ectopic pregnancy is a recognized complication following assisted reproductive technolo...

Purpose The aim of the present prospective study was to investigate the efficacy of hyaluronan (HA) using two different concentrations as embryo transfer media for in vitro fertilization embryo transfer cycles. Methods A total of 169 cycles undergoing fresh embryo transfer on day 2 or 3, 561 cycles undergoing frozen-thawed embryo transfer on day 2 or 3, and 484 cycles of frozen-thawed blastoc...

BACKGROUND The absence of reliable markers for the identification of viable embryos for transfer at the early cleavage stage is likely to contribute to the generally low implantation rates and high incidence of multiple gestation in IVF treatment. In this study, we investigate the relationship between timing of first cleavage and the incidence of blastocyst formation in vitro. METHODS Couples...

BACKGROUND The respective advantages of day 3 and day 5 embryo transfer are a matter of debate. Previous comparisons did not include pronuclear stage zygote scoring and cumulative success rates (fresh and cryopreserved embryos). METHODS Patients were randomized prospectively for day 3 or day 5 embryo transfer. Day 3 embryos were selected for transfer and cryopreservation by using combined eva...

Although improved outcomes of IVF after transfer of blastocysts has been reported (1, 2), it remains uncertain which blastocyst can develop into a viable fetus. At present, expansion of the blastocyst is the most practical selection criterion. However, if extended culture of embryos produces many expanded-stage blastocysts, it is not easy to decide which blastocysts to transfer (Fig. 1A). In ad...

This study was designed to examine the effect of the age of rabbit oocytes on the developmental potential of cloned embryos. The metaphase II oocytes used for nuclear transfer (NT) were collected at 10, 12, 14, and 16 h post-hCG injection (hpi). The total number of oocytes collected per donor (21.4-23.7) at 12 to 16 hpi was similar, but significantly higher than that collected at 10 hpi (16.2)....