Clinic quoted "about 35% per transfer" at our follow-up. What does that number actually mean at 38?

We had our follow-up after the failed cycle last week. It was kinder than I expected, and mostly useful, but one moment has been rattling around my head since: the consultant said that for someone in my situation, I'm 38, the chance is "about 35% per transfer".

I nodded like a person who understood, then came home and fell down a hole. One clinic website near us advertises 45%. A thread I found says it's really more like 1 in 4. Another site quotes a completely different number "per cycle started". They cannot all be describing the same thing, surely?

So, people who've been at this longer: what does "per transfer" actually mean? Does it include the cycles that get cancelled or where nothing makes it to transfer (we nearly were one of those)? Is 35% considered good at my age? And the question I'm scared to ask out loud: what happens to that number at 39, at 40? We have one more year of trying in us, maybe two, and I want to spend it on real numbers.

Oh, the numbers hole. I've lived in it, four cycles' worth, so let me hand you the ladder I eventually found.

The single most useful thing I learned: a fertility statistic means nothing until you know two things about it, what's on the bottom of the fraction, and what counts as the finish line. "Per cycle started" and "per embryo transfer" are different bottoms: per transfer looks higher because it quietly excludes all the cycles that got cancelled or never produced an embryo to transfer, and we had one of those, so I felt that difference personally. And "pregnancy" versus "live birth" are different finish lines: the pregnancy rate is always the bigger, shinier number, and it is not the one you actually care about.

Once I understood that, the gap between your consultant's 35% and that clinic's 45% stopped looking like a contradiction and started looking like two different fractions. My rule since cycle two, whenever anyone quotes me a number: I ask "of what, counting what?" out loud, in the room. The good clinicians never mind. The site's piece on age and fertility was also the thing that finally made the WHY behind the age bands click for me, if you want the mechanism and not just the maths.

Partner and household spreadsheet-keeper here. The reframe that helped us most: stop reading the per-transfer number as a verdict on one roll of the dice, and ask the clinic for the cumulative picture instead.

A number like 35% sounds like a coin toss you keep losing. But when our clinic laid out the estimated chance across the two or three transfers we were actually planning, the cumulative figure was meaningfully higher than any single-cycle number, and suddenly we were making a plan instead of bracing for a verdict, if that makes sense. It changed the emotional weather in our house more than any single piece of information in the whole process. Ask for it at your next appointment; they have it.

Louise, this is one of the most important questions on the site, and gemma and Dhruv have already done half my job. Let me answer it directly and then give you the checks.

"About 35% per transfer" means: of embryo transfers performed in patients like the group being described, roughly 35% ended in the outcome being counted. Before you compare it with anything, ask three questions of every number. First, per cycle started or per embryo transfer? Per transfer is always higher, because it excludes cancelled cycles and cycles with no embryo to transfer, exactly the near-miss you described. Second, pregnancy or live birth? Live birth is lower and is the number that matters. Third, whose results: a whole-clinic average, your age band, or an estimate personalised to your own history? A headline figure on a clinic's website is usually the most flattering combination of those three, which is why marketing numbers compare so poorly; the standardised figures that regulators publish are counted the same way for everyone and are far more comparable.

On age, honestly: per-cycle success is highest under about 35 and declines with age, more steeply from the late thirties, because egg quality declines, so yes, the estimate at 39 or 40 will be somewhat lower than today's. That is a reason to want personalised numbers now, not a sentence. And Dhruv's point deserves underlining: because each cycle has a limited chance, the cumulative estimate over the transfers you're actually planning is often the more realistic planning number, and many people who succeed do so after more than one attempt. The site's guide to how success rates are counted covers all of this in one place.

The number that should carry the most weight for you isn't on any website: it's the estimate your own clinic builds from your age AND your two cycles, which contain real information about how you respond. That's a follow-up question, and they will expect it. And one thing a probability can never tell you: which side of it you're on. 35% happens to real people every single day.

At 41 my quoted numbers were smaller than yours, and the thing that eventually gave me peace was realising a percentage is a fact about a thousand strangers, not a prophecy about me. It deserves a seat at the table when you plan. It does not get to grade you afterwards. Holding your hand from the 41 corner.

Update, because this thread rebuilt me a bit. Went back to the clinic with three questions written down: counting what, of whom, and cumulative across the transfers we'd realistically do. Got straight answers to all three, including an estimate based on our own two cycles rather than the age-band average.

The decision ahead of us is still hard. But it's OUR decision now, made on real numbers instead of a scary soup of other people's fractions. Thank you, all of you, especially for "of what, counting what", which I will be deploying for the rest of my life.