In scientific and procedural collaboration with Dr. Graubert, Dr. Roseff has successfully established a blastocyst transfer program for couples undergoing IVF. This exciting program promises to maintain, or possibly to increase, our IVF success rate while decreasing the number of high-order (triplet and quadruplet) pregnancies (which can be associated with serious complications to both children and the mother).
HOW DOES A BLASTOCYST DIFFER FROM AN EMBRYO?
After egg retrieval, the fertilized egg
may develop into an embryo over a period of three days in the laboratory. The embryo
typically divides into between 4-10 cells. The outer shell that typically surrounds
an embryo is rather thick on the first few days following fertilization, and often these
embryos will require "assisted hatching" to assist the escape of the embryo from
its shell. A blastocyst, by comparison, is an embryo that has advanced to the
five-day or six-day stage; which means the embryo has divided many more times into many more cells
over the five- to six- day period following an egg retrieval. Blastocysts have a very thin
outer shell and do not require assisted hatching, thus potentially increasing the odds of
implantation into the uterine cavity. While the majority of fertilized eggs will
develop into a three-day old embryo, only approximately half of these embryos will develop
into a blastocyst. Therefore, blastocysts are considered to be a more
"select" group of embryos with a higher chance of implantation.
WHAT ARE THE ADVANTAGES OF BLASTOCYST TRANSFER?
Because blastocysts are a more advanced and select group of embryos, and
because they are more likely to implant, we are able to transfer only two blastocysts in
order to achieve the same pregnancy rate we would expect from transferring three, four, or
more three-day old embryos! This will reduce the probability of a triplet or
quadruplet pregnancy to almost nil. You must be aware, however, that a blastocyst
can divide into an identical twin after it is transferred to the uterus, and so there is still a very small possibility that two
blastocysts can result in a triplet pregnancy. The chance of a blastocyst dividing
into two identical embryos is estimated to be as low as approximately 1 in 350
to as high as 1 in 20. Because blastocysts are more
likely to implant, there still is a very good chance of a twin pregnancy being established
when two blastocysts are transferred. In fact, the chance of a twin pregnancy is as
high (or possibly even higher) when two blastocysts are transferred as compared to when
four three-day old embryos are transferred.
WHAT ARE THE DISADVANTAGES OF BLASTOCYST TRANSFER?
As stated above, it is more difficult for an embryo to develop into a
blastocyst. Therefore, there is the possibility that an IVF cycle will not result in a
transfer of any embryos if none of the three-day old embryos develop into blastocysts.
We believe that if blastocyst development does not occur, it is highly likely that
a pregnancy would not have developed if the embryos had been transferred at the three-day
old stage. Nevertheless, it may be difficult to accept having gone through an IVF
treatment cycle and not having the chance of becoming pregnant through the transfer of any
type of embryo. We can view this, however, as a possible advantage of blastocyst
transfer -- if the embryos are not going to develop into blastocysts, and if a pregnancy
would not likely have been achieved by the transfer of earlier-stage (three-day old)
embryos, then the time, expense, and the waiting for two weeks to find out if a pregnancy
had occurred can be eliminated.
HOW DO I DECIDE IF BLASTOCYST TRANSFER IS FOR ME?
We are currently recommending blastocyst transfer to those patients who have
a better chance of having blastocyst development (i.e. younger women with a reasonable
number of good quality embryos). Most of these blastocyst transfers have in fact
resulted in pregnancy (ask us about our IVF success rate). As
the world gathers more experience with this new treatment
modality, it is very likely we will recommend this procedure to the vast majority of our
patients. Blastocyst transfer is also recommended to those who have strong concerns
about delivering high-order multiple pregnancies, and for those who would not undergo
fetal reduction. Finally, we believe blastocyst transfer is an excellent choice for
most women who undergo a frozen embryo transfer cycle. The embryologists can
thaw most (or all) of the frozen embryos and see which ones develop to the blastocyst
stage (which, again, would be inherently more likely to implant and result in a successful
pregnancy). If more than two blastocysts develop, the remaining extra blastocysts
can be frozen for use at a later date.
In the end, the embryologists are in the best position to make recommendations regarding whether you should undergo a 3-, 4-, 5-, or 6- day embryo transfer. Following your egg retrieval, you will be apprised of their suggestions as time passes and the total number and quality of your developing embryos becomes evident.
For our latest IVF success rate,
Go to our Pregnancy Success Page
If you have any questions regarding any of the above, please call or e-mail us.
561-333-8232
E-mail: doc@reproendo.com
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