Should I worry about a drop in percentiles at 33 weeks?

[Starryalex]

I had a growth scan today as I’ve had two previously big babies. This baby had so far been measuring average but after today’s scan the doctor said it had dropped from the 40th percentile to the 18th. She isn’t overly worried and said there’s about a 20% margin of error but I’m still worried that it means there’s something wrong. They’re having me come in again next week to check placenta function etc and then another growth scan the following week so I feel reassured that they’re watching things closely. Just wondering if anyone has had anything similar happen and how it turned out?

We went from the 55th to 19th at 32 weeks. Got scanned again 2 weeks later and he was 22nd. He was born on the 22nd percentile. Seems that the 55th percentile was the outlier and an inaccurate measurement. I wouldn't worry too much right now! As scans are notoriously inaccurate.

@AnonKat thank you, that’s reassuring! Measurements were all in line for how many weeks I am and estimated weight of about 4lbs which seems average for 33 weeks so I’m trying not to over think it. Only worry was that growth had dropped but I’m hoping it was due to baby’s position or even the fact that the scans were done by two different doctors. I have another growth scan in two weeks so hoping all will be ok then and I can relax a bit!

I’ve had growth scans all the way through this pregnancy as my previous babies had fetal growth restriction and where 3rd and 1st centile, at 28 weeks I was told she’d dropped from 49th to 15th to come back at 31weeks went back last week and she’s up to 56th centile!! The consultant said was probably mistake in measurement at the time! ☺️

I had growth scans with DD1 and she went from 75th to 50th to 18th to 9th by 37w (or numbers around there - i forget precisely now she is 5y!). At that point, they booked an induction for a week later. She came spontaneously at 38w but the consultant didn't seem bothered until she dropped below the 10th. At the point of giving birth, my BP was very high (and I had preeclampsia with DD2) so i think there was maybe something going on causing the growth slowdown.

Edit to add - she was 5lb 12oz (2.6kg) at 38w so she was pretty little and the growth scans were reasonably accurate in my case.

Mine dropped down to 10th centile but they didnt seem overly concerned just extra growth scans. He was small when born 6lbs but hes now 2 and perfectly healthy