Thursday, September 20, 2012

Should you ask your IVF doctor to do PGD for you ?

While the academic debate about the true utility of PGD may rage on , the question which patients want an answer to is simple – Doctor, should I do PGD or not ? The answer to this is exactly  like the answer for lots of other vexed issues in medicine – it depends !

It depends upon:

what your worldview is and how aggressive you want to be in your treatment
how fed up you are
how many IVF cycles you have failed
what your medical problem is
which clinic you go to

PGD should still be considered to be a research tool , and is best used in an experimental setting , so that we can collect and analyse data in a controlled clinical trial, to evaluate whether doing routine PGD for all patients actually ends up improving pregnancy rates. While common sense suggests that PGD should improve pregnancy rates, we all know that in reality biology doesn't always follow logical rules - and only controlled clinical trials ; and time and experience will tell us what the truth is . Because it's such a complex questions , there are likely to be lots of different answers , depending on whom you speak to . This is why it's important that patients have realistic expectations and be well informed , so that you know exactly what you are going in for .

Part of the problem is that clinics which aggressively promote the use of PGD engage in marketing hype. They are invited to give lectures at a lot of medical conferences , because PGD is considered to be cutting edge technology ; and doctors want to learn “what’s new” ! They present PGD as being the state-of-the-art technology; and are quite dismissive of “old-fashioned” clinics which do not offer this. Many IVF clinics suffer from an inferiority complex if they do not PGD; and many suffer from “PGD envy” . Many doctors still naively believe that more is better – and will look upto experts who use technology which they do not have access to.

To add to the problem, thanks to the internet , patients  read a lot of success stories from women who have failed multiple IVF cycles , and then got pregnant after going to clinic X which did PGD for them. It’s very easy to fall into the classical logical fallacy of post hoc, ergo propter hoc; and when we read newspaper articles about these success stories, we automatically assume that it was doing the PGD which led to the ultimate success. In reality , whether it was the PGD which helped them to achieve their pregnancy ; or whether they would've got pregnant in any case on their nth attempt, even without doing PGD , is something which we will never really know ! While the patient is happy to give credit to the PGD; and the clinic is happy to take this credit, often this is not really deserved at all !

Let’s look at this a little more closely. CCRM is one of the world’s leading IVF clinics; and is a big proponent of PGD . One of my expert patients pointed out a very interesting fact to me. “ I just went through the papers CCRM has published on how PGD helps to improve pregnancy rates. In 2011 they published a paper on CCS ( comprehensive chromosome screening ) and they said they achieved an implantation rate of (a beating fetal heart beat per embryo transferred ) of 68.9% ; while in their control group of patients (without CCS) , their implantation rate was much less - only 44.8%. This would suggest that PGD and CCS is clearly superior !

If CCRM can achieve such high pregnancy rates, then why shouldn’t all other clinics be able to do so ? Does this mean that other clinics are not as good as CCRM ? That CCRM is technologically superior ? Is it that other doctors are not doing PGD because they're envious of the special skill sets which CRM
offers ? Does CCRM have a “magic sauce “ which other clinics cannot replicate ?

However, I then went through a CCRM paper on blastocyst transfer published in 2001 ( CCRM was the first clinic in the world to popularize blastocyst transfer) . At that time ( over 10 years ago !) they reported that transferring two good blastocysts lead to an implantation rate of 69.9% . This means they achieved the same ( very high) implantation rate in 2001 without doing CCS, as they did in 2011 after doing CCS ! This clearly shows that CCS does not help at all ! How could their implantation rate in 2011 in the control group ( without doing CCS ) be only 44.8% (in 2011) when in 2001 they said that with the transfer of two good blastocyst (without CCS) they achieved an implantation rate of 69.9%? “

If you dig deeper, like my expert patient did, it seems that the CCRM success rates 10 years ago ( when they first started doing blastocyst transfer without doing PGD ) were as good as they are today, 10 years later ! This causes you to wonder if CCS helps at all ! Or whether there is some other factor at play.
We need to accept the fact that research can be complicated; it’s not easy to find the truth ; and that we shouldn't rely on just one single study to come to conclusions.  This is why most doctors prefer remaining conservative , until we have better data from more centers.

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