The embryos were then transferred to recipient women. They had pregnancies when the recipient's cycle was from 4 days in front of to 3 days behind the donor's uterus at ovulation. This suggests a window of implantation of up to 7 days. Navot et al, in 1991 reported on donor embryo transfers done with 2-3 day old embryos on recipient cycle days 15-20 (artificial cycles controlled with meds).
Making the world better, one answer at a time. Catalysts are never consumed in the reaction. that's what makes them catalyst! not a reactant. they increase the rate of reaction by lowering the activation energy for the reaction. One of the ways to do this by providing an alternative route for the reaction to follow.
A catalyst catalyst: A catalyst changes the rate of a chemical reaction without being changed by the reaction itself. is a substance that can increase the rate of a reaction.