Going to Blast! Part 2.

So yesterday we discussed blastocyst transfer in general and today we get down to brass tacks…You know, it amazes me that some of the Residents and Medical Students that I teach do not know some of these quaint little sayings like the one I just used. I have said to them “a watched pot never boils” and received just blank stares. Is this a sign of advancing age on my part or is it because they watched too much TV as kids? I have no idea. All I know is that it still really disturbs me that the 80s music that I listen to in the operating room was released before some of the medical students were born! Yikes.

In any case, back to blast transfer. So how do we choose? That is the “Question of the Day.” So if you are wracked with guilt over reading these questions for free rather than buying the book 100 Questions and Answers about Infertility, then ease your guilty conscience and click over to Amazon.com pronto!



70. My clinic allows me to choose between a day­3 and a day­5 embryo transfer. How do I
decide?

The decision to transfer embryos on day 3 or day 5 is one that requires careful thought. In general, embryos that have formed blastocysts have a better chance of implanting successfully. Unfortunately, not all embryos will progress to the blastocyst stage outside of the body. This inconsistency raises the question as to whether the embryos that fail to form a blastocyst would have initiated pregnancy had they been transferred back into the uterus on day 3. Some studies have, indeed, demonstrated acceptable pregnancy rates with day-3 transfers of embryos that were of marginal quality and that, based on historical data, would have been unlikely to form blastocysts in culture. Clearly, the pregnancy rate in the absence of an embryo transfer will be zero, whereas even embryos of borderline quality, if transferred on day 3, may potentially lead to a pregnancy.

So how can you decide between a day-3 and a day-5 embryo transfer? Many clinics make the decision on day 3. If a patient has a certain number of high-quality embryos on day 3, then the embryos are maintained in culture for 2 additional days to allow for further embryo selection at the time of transfer. If the embryos fail to progress to the blastocyst stage, however, then there is no transfer—which often results in profound patient disappointment. If a limited number of embryos are available on day 3 and no embryo selection is needed, then the benefit of a day-5 embryo transfer may be limited.