Can you explain centile to me? This is my first pregnancy

[Hodge85]

Hi,

So today I went for a re-scan for my 20 week scan as my little boy loves to be awkward! I'm 22+2 and I can't believe how much he's grown since my last scan 3 weeks ago. Anyway, they've said he weighs 1Ib 4ozs and measured his abdominal circumference and femur length which is what these lines represent. Does this mean he's measuring bigger? I don't understand the whole centile thing so any help would be great, thanks!

50th centile means exactly average. 25th centile is small - 75% of babies will be bigger. 75th centile is large - only 1/4 babies will be bigger.

As long as they're all vaguely in the same area that's fine.

Think of it like percentages. E.g. if someone is on the 50th centile for height, then 50% of the population will be taller and 50% shorter than them; if someone is on the 2nd centile then 2% of the population is shorter than them and 98% are taller.
The horizontal line goes from 1st centile on the left to 100th centile on the right, with 50th exactly in the middle. It looks from the image as though those measurements are roughly 75th/80th centiles.

Not sure if that answers your question?!

Centiles basically indicate where your baby measures compared to all other babies of the same gestation/age. A completely average baby would be the 50th centile.

For example: My own baby is on the 25th centile for weight. Compared to all other babies her age, 75% of those babies weigh more, and 25% weigh less. If there was a line up of 100 babies all born on the same day as mine, 24 would weigh less and 75 would weigh more.

The lines on the results show what is considered the normal range.
So it's:
5th -- 50th -- 95th
And the dot indicates where in this range your baby lies.
So (assuming this is what is measured) your Crown Rump Length looks to be about on the 80th centile, the middle value (abdominal or head circumference?) is about the 75th centile, and the estimated weight is around the 85th centile.

So all in all, at the moment, you have a slightly larger than average baby for its gestation, but one that is completely within normal ranges.

Ah thank you all, that makes much more sense now! I wasn't sure how it worked but now I do, thank you!