blast off

just when we though we were in the clear.  we did get good news this morning as all four embryos are still kickin', however, the next 24 hours is very important.  they will transfer the embryos to a new medium today to hopefully develop into blastocysts.  let me attempt to explain...up until several years ago this would be the day of transfer.  because on day three it is difficult to predict what embryos would be most likely to result in pregnancy four or more embryos would usually be transfered with hopes that at least one would result in live birth. the downside is that sometimes all the embryos become ongoing pregnancies and the result is high-order multiple gestations (triplets or greater).  In such pregnancies there are considerable medical risks as well as financial and emotional.  So the couple would be faced with the agonizing decision of whether to opt for selective reduction (the removal of one or more embryo) or to continue with a risky pregnancy. 

however, with blastocyst transfer, only two or three embryos are transferred practically eliminating the possibility of triplets or greater.  and the same pregnancy rates are achieved as would be expected when four or more embryos are transferred on day three.  i should probably mention that a blastocyst (referred to as blasts) is a highly developed embryo that has divided many times to a point where it is nearly ready to implant on the walls of the uterus.


during maturation, an embryo rests inside a protective shell called a zona pellucida.  you can think of this protective shell as being much like a chicken egg.  but, unlike chicken eggs, human embryos do not remain inside a shell.  instead, the embryo hatches (breaks out of the shell) on the fifth or sixth day so it can attach to the uterine wall (implantation).  just prior to hatching an embryo becomes a blast.

embryos developing to the critical blastocyst stage have a much greater chance of implanting successfully and resulting in an ongoing pregnancy.  that is because these embryos have passed an important test.  during the first few days, the embryo relies on the mother's eggs for all its  nutrients.  however, in order to survive past day three or four, the embryo must activate its own genes.  not all embryos are successful.  yet, these embryos are more highly-developed, healthier, stronger and have a higher rate of implantation when compared to day three embryos.  due to higher probability of survival, they only have to implant one or two blasts.

clear as mud?  in know, welcome to my world.  i better wrap up for now and try to figure out how in the hell i am going to get through the next 24 hours.  i have an acupuncture appointment this morning so hopefully shamayne can balance me out a bit.  oh yeah, josh gave me my first intramuscular shot last night and it wasn't bad at all.  i am starting to think he should go to medical school:)  maybe that is how we can pay for all of this...