2013-10-18

“The odds are in my favour, man” (Don’t break the rules, Catch me if you can)

So at the moment I’m ‘Pregnant Until Proven Otherwise’ – that’s pretty cool. We had such a wonderful positive experience at the frozen embryo transfer yesterday that I have even been feeling quite hopeful. It was so good to have the embryologist say that in her professional opinion it is unlucky that we’ve not succeeded with the IVF yet and that it is very likely that we’ll see success soon. This time, hopefully.

I used to know about statistics. I have an A Level in Maths and an AS Level in Further Maths. My job has a statistical component. But I’ve forgotten much of what I used to know and the stats around this IVF stuff are rather complex.

But it seems like the deal is that when implanting a top quality blastocyst for IVF the chance of pregnancy is 50%. This is simply because half of all blastocysts in the world (not just IVF) are not genetically viable. Just the way it is – why it usually takes any normally fertile couple a few months to get knocked up. Anyway, what this means is that on any given try at IVF with these circumstances there is a 50/50 chance that it’ll work.

So this is the same as tossing a coin and looking for heads. On each individual toss you need to accept that you might not get heads, but the more times you do it the more likely you are to get heads. Toss it once you might get heads. Toss it twice you’ll probably get heads at least once. Toss it three times and you’d be really unlucky not to get heads at least once. So we’re on IVF toss number three. We’d be really unlucky not to get a positive by toss number three. It can happen that you toss a tail three/four/five times in a row, but it is pretty unlikely. So it could happen that we’d have failed IVFs three/four/five times in a row, but it is pretty unlikely.

Alternatively you could think about it this way. Imagine you had a bag of eight snooker balls containing four green balls and four red balls and you wanted to pull out a green one. You might pick a green one the first time. Or, you might pick out four red ones in a row and not get a green one until the fifth go. We started with eight embryos of equally good quality. With 50/50 odds we expect half to be good and half to be crap. We’ve just pulled out two ‘red balls’ in a row. We might still pull out another two red balls before we get a green one.

But that’s just the layman’s explanation. It is much more complicated than that. There’s a lot we don’t know. It is all guesswork and medical science does not allow us or the doctors to know much at all. This 50/50 stuff is not exact and is not based on comparing like with like. Actually we know nothing. All our embryos might be tails of the coin or red snooker balls and we won’t know until we’ve used them all up. Then we won’t know if that was bad luck and we might see success if we started again with a new batch, or whether we have an underlying condition so unusual that the NHS can’t identify or treat it.

Really it is hard to judge anything from anything and to know how hopeful to be.

There’s a lot out there on the web about people who went against the odds and got pregnant from IVF in very difficult circumstances – following several cancelled cycles, having collected only one egg, with unpleasant medical conditions, without age on their side, with poor quality embryos. It is very easy to find advice and success stories if you are in this position. Fair play, I suppose most people who need ‘assisted conception’ need their conception to be assisted. Obviously. But what I mean is most people doing IVF have a problem that can be fixed by artificially creating the ideal conditions.

It doesn’t look like that is our problem.

There’s not much out there for you if you have every single thing on your side and it still doesn’t work. If you’re under 35, if you have a healthy lifestyle, if your weight is within the recommended parameters, if you have responded well to every element of the IVF process with no problems, if you’re not stressed out of your box, if you have generated a handful of embryos and they have all survived to be exceptional quality blastocysts.

Hypothetically, like.

I have no idea if IVF will work for us. And if it doesn’t work, why it hasn’t worked. The doctors have no idea either. All they know is that in their experience it should have already worked by now for us. So it probably will work at some point. Probably. Maybe this time.

Just got to plod on with it I suppose.

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