99% of all statistics only tell 49% of the story……..!! Interpreting fertility clinic success rates
We proudly published the 2013 pregnancy rates on our website and clearly we are delighted to be able to show an increase across the board from 2012
I was originally thinking about starting my first ever blog piece with the better known saying “Lies, damn lies and statistics” but although probably very appropriate for Benjamin Disraeli to say about some of his 19th century political opponents, perhaps less appropriate as a starting point about our newly published success rates!
Instead, financial guru Ron De Legge’s phrase (never heard of him?……..nope neither had I!!) was a better starting point to help understand clinic success rates and how to interpret them.
We proudly published the 2013 pregnancy rates on our website and clearly we are delighted to be able to show an increase across the board from 2012 – justifying all the hard work by the embryologists in the lab, by the nurses in guiding people through treatment and the decisions made by the medical staff in conjunction with their patients. The figures also remain significantly higher than the national average that is available on the HFEA website.
Although the HFEA website is an excellent source of independent information, it can be a very difficult process teasing out all the data you want and interpreting it. More importantly, when you compare clinic with clinic are you really comparing like for like? Here are some things to think about in making your comparisons!!
1. What outcome are you being given?
There are two main outcomes of interest. The first is “Clinical pregnancy rate” (CPR) which is the number of pregnancies that get to the point of seeing a heartbeat on scan and the second is “Live birth rate” so the number of babies actually born. Our data for 2013 is for CPR, so far as many of those women who we treated last year are still pregnant. So it’s important that you compare the same type of pregnancy rate! Perhaps just as importantly is the multiple pregnancy rate. Our aim is to get mum and baby home, happy and healthy, and the best way to do this is to avoid the risks that come with twins and triplets. So ideally a clinic should have a high pregnancy rate while trying to minimise the multiple rate……..although that’s a whole other blog piece!
2. Who do clinics treat?
No two IVF clinics are the same! Fertility clinics have different criteria on who they are willing to treat, based on factors like age, markers of ovarian reserve (such as FSH and AMH) and previous treatment history. Some clinics use these markers as a tool to ration treatment to those who may have a better chance of success.
Our philosophy is to treat all patients with potential to succeed! We don’t believe that the final decision on whether to treat should be ours alone. We use these tests as counselling tools to ensure we have accurately advised patients of their chances and those with a low likelihood of success should also be offered treatment if they wish. Our own pregnancy calculator is a mini version of the geeky stats available to us in clinic that we use to guide people through their chances of success.
It’s always worth going to open evenings to get a feel for how clinics operate, chat to the clinicians or other patients who have gone to a clinic. Perhaps ask about any predetermined cut-off values that the clinic may have? You have to feel comfortable with the ethos and atmosphere of a clinic!
3. Abandoned cycles?
This is a good tip on getting a feel for a clinic’s data. The HFEA have shown that nationwide over 9% of women who start treatment do not get to egg collection and 14% of women do not get any embryos to transfer. There are many reasons for cycles to be abandoned. Women may not respond to the drugs or they may over-respond, get hyperstimulation and have to cancel before egg collection or they may not get eggs that fertilise.
It is impossible to not have any abandoned cycles – or to only have a few – and if that is the case, it may again be a sign that only very good candidates are being offered treatment.
So, hopefully I’ve given you a few things to think about. We are very proud of our recent success rates as well as 25 years of success based on a philosophy of treating everyone that comes through our door. If we then do what we do to the best of our ability, our stats will still look great and more importantly tell the whole story and not 49% of it!!
James Nicopoullos is a Consultant Gynaecologist specialising in reproductive medicine, assister reproduction and male fertility at The Lister Fertility Clinic.
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