Can someone explain the centile chart?

[penguin7]

Can someone explain the centile chart? It's my first pregnancy and yet to have my measurements taken however after reading various threads on here I see people talking about 50th centile, 80th centile, 90th centile etc...
I will ask my midwife as/when the time comes for my measurements just curious to know and understand about it now.

If you lined up 100 babies, the 20th along the line would be the 20th centile, the 50th the 50th and so on. Think if it as “position out of 100”.

Does that help?

It is just the range of normal growth, so just about all DC will be somewhere within that. They usually expect them to stay on about the same centile as they grow, and if they go up or down significantly it can be a sign of a problem. So for example my DC has been between the 2nd and 9th centile his whole life, which means he is on the smaller side but within normal range.

So if thinking about weight, the baby in position 1 would be the lightest and the one in position 100 would be the heaviest.

A baby on the 90th percentile for weight is heavier than 90% of babies at the same gestation. A baby at the 5th percentile is heavier than 5% of babies i.e. 95% are heavier.

Yes it does make sense now thank you...so is this what midwife will start doing at my next appointment (I will be 28 weeks then)?

Centile don’t come into play until baby is born.

@NavigatingAdolescence

Centile don’t come into play until baby is born.

Actually, there's a fundal height centile chart (measurement of belly area) to give an indication of baby size, position of baby, amniotic fluid, etc. This is measured from 28 weeks pregnancy and you should progress along the chart at a steady range. For example, if you measured 50th centile, you should stay around 50th centile range at following appointments. If you jumped or dropped centiles significantly, you'll be invited for extra scans.

Centile charts very much are involved before baby is born.
I'm having growth scans due to history of big babies. My current is on the 97th centile atm, means that out of 100 babies the same gestation only 3 would be bigger/heavier. Scans are estimates though and can be out by up to 25% so not as accurate as after birth measurements are.

@Chelyanne

Centile charts very much are involved before baby is born. I'm having growth scans due to history of big babies. My current is on the 97th centile atm, means that out of 100 babies the same gestation only 3 would be bigger/heavier. Scans are estimates though and can be out by up to 25% so not as accurate as after birth measurements are.

Quite. My scan at 40 weeks was pointless. “Baby is some where between 7lbs and 9lbs.”

As are the vast majority of babies.