Wednesday, April 01, 2015

Why sequential embryo transfer is a bad idea

All IVF doctors want to maximise the chances of their patient getting pregnant . We know that if we transfer more embryos , the chances of getting pregnant increases, which is why there’s often a lot of pressure to transfer more embryos back.  Sometimes doctors do what is called a sequential transfer, which means they will transfer embryos on Day 2 or Day 3; and then continue growing the other embryos to Day 5, at which time they will then transfer these additional blastocysts as well.

Now from the patient’s point of view, they seem to be getting the best of all possible worlds. Since a transfer is occurring on day two, they know that they’ve had a successful transfer, which means they don’t need to worry about the possibility that the embryos may arrest in vitro and not form blastocysts in the lab.  Since the doctor is also transferring blastocysts , which have a higher implantation rate as compared to Day 2 embryos, this seems to be a method by which they can have their cake and eat it too !

This is one of the reasons why doctors often offer this option to patients, but it’s not a good option in my opinion. One of the reasons is that transferring too many embryos doesn’t increase the chances of getting pregnant, it just increases the risk of a multiple pregnancy . It makes much more sense to just transfer one or two good quality blastocysts , rather than to transfer blastocysts plus Day 2/ Day 3 embryos. 

Typically the sequential transfer option is used by IVF clinics which aren’t very confident about their laboratories , and are not very sure whether they are capable of growing the embryos to blastocysts.  They actually use this in order to cover up their incompetence as a risk mitigation technique , so that they can transfer some embryos back into the uterus , thus keeping the patient happy . This way, even if the other embryos do not grow well in the laboratory, the patient will not complain.  Good labs never do this because they are confident enough in their ability to be able to grow embryos to blastocysts routinely , and therefore they will only transfer embryos at a blastocyst stage. They could transfer either a single blastocyst or two, depending on the patient’s clinical context and preference.  Thus , if your doctor tells you to do a sequential transfer, you should worry a lot. 

However, let's suppose you opt for a Day 5 transfer, and all your embryos arrest in vitro ?  There is no question that this is a tragedy, but in a good clinic, if an embryo arrests in vitro in the lab, this means that this embryo would not have developed in utero either, This means that it would never have implanted and become a baby. By doing a Day 5 transfer in a good IVF lab, you haven’t reduced your chances of getting pregnant, which would have been zero in any case. More importantly , you’ve saved yourself the agony of a two week wait, which would have ended in a negative result.

The key difference is the competence of the IVF lab , and how well they are able to grow embryos into blastocysts.  Labs which do this routinely and are confident of their technical expertise, will prefer transferring one or two embryos on day five, rather than use a hodge-podge of sequential transfers in order to cover up for their lack of confidence in their technical skills.

Looking for an IVF clinic which specialises in blastocyst transfers ? Please send me your medical details by filling in the form at so that I can guide you better !

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