A simple nonsurgical technique to obtain unimplanted eggs from human uteri

Optimizing embryo selection with day 5 transfer

“…Considering that in vivo embryos typically do not reach the uterus until at least the morula stage 4 days after fertilization (40), cleavage-stage embryos may be too physiologically immature to be exposed to a potentially asynchronous uterine environment (41) and may be deprived of the nutrition that the oviduct would provide (42). Other investigators have cited that there is less chance of embryo expulsion with blastocyst transfer due to decreased uterine pulsatility (43).…”

Pre-Implantation Development

“…The other design of catheter has three lumina, one for bulb inflation as before, a second for fluid injection and the third for fluid return (which with this device can be simultaneous with injection). (Detailed descriptions of these techniques are given by Croxatto et al, 1972;Hunter, 1980;Brackett et al, 1981;Buster et al, 1983;Trounson, 1983;Bavister et al, 1984;Betteridge, 1986;Brambati and Tului, 1990.) Loskutoff et al (1990) describe the nonsurgical transcervical recovery of embryos from the uterus of the suni (Neotragus moschatus zuluensis), a small East African antelope, and give references to similar work on other African ungulates.…”

Optimizing Embryo Transfer Outcomes: Determinants for Improved Outcomes Using the Oocyte Donation Model

“…However, unlike in-vivo embryos that normally travel through the fallopian tube and do not reach the uterus before the morula stage (four days post-ovulation), in-vitro cultured embryos that are transferred to the uterine cavity at the cleavage stage may be subjected to stress that normally would not occur. Some have argued that this environmental milieu and possible higher uterine contractility during cleavage stage ET results in expulsion of earlier transferred embryos and may account for the exceedingly high implantation failures seen in most IVF programs (Croxatto, 1972;Fanchin, 2001;Valbuena, 2001).…”