Growth scan dropped to 10th percentile at 30 weeks?

[Lillly1]

I’ve just had a growth scan and the baby’s measurements have dropped to an average of 10th percentile.

At the 20 week scan the average was 30th percentile, with the head circumference alone above the 50th percentile.

I can’t help but think this isn’t a good sign. Has anyone been in the same boat?

Similar happened to me between 30-34 weeks baby's growth seemed to slow right down and was on 12th%. Had been 44th% at the 20 week scan.
Went back for growth at 36 weeks at it was 47th% again! Can't really explain, dopplers and fluid were always normal. 39 weeks now with no intervention as all stayed normal again. Best of luck OP

I was told my baby was in the 90th percentile and when my son was born he ended up being in the 6th instead! Ignore percentiles. My boy has turned out fine and is one of the tallest in his class 🤔

I had so many growth scans! 4 weeks before born measured 20th centile, dropping from 60th or so earlier on. They did consider delivering early but everything else was perfect. Fluid volume fine, blood through cord fine, textbook CTG trace, very active baby. So on balance decided in my case that due to margin of error in scans that it would be ok with extra monitoring. He was born on 80th centile, over 91st for length. He was huge 😅.

I had this. 20wk scan was fine. Had to have an extra scan for a low placenta at 30 weeks, and baby's tummy measurement was 2nd percentile.

Went back for extra scans weekly and baby got to 15th percentile for tummy measurement by 36 weeks. Consultant was happy for this and got signed off. Currently 40+4.

Apparently the middle measurement is very difficult to get bang on, and can vary a lot with ultrasound technique. Also it's the squishiest part of the baby, which also impairs measurement. Therefore it can skew results somewhat when calculating the average. Also having a very tall / short baby has an impact.

Also babies put on a lot of mass towards the end of pregnancy. Especially if you've had any health issues during earlier stages (in my case stubbornly low iron was mentioned as a potential factor).

This happened to my DD1. By the 36w scan, she had dropped below 10th centile so i agreed to induction at 39w, but in the end she made a spontaneous appearance at 38w. She was 5lbs 12oz so quite a little one. In the last week of pregnancy, my blood pressure went very high and in my second pregnancy (also with a small baby), i developed preeclampsia so i suspect for me the two things were related.

If baby's growth continues to drop, they will start to talk about getting baby out sooner rather than later. Have you done your antenatal classes yet? If not, have a read up on your options (waiting, induction, elective c section etc) and make sure you think about any questions you might want to ask.

Thank you so much all for the reassurance. I am booked in for a c-section for medical reasons anyway so if they decide to bring that forward I would be okay with that.

Actually last night I looked at the chart and I’m not entirely sure she plotted the dot in the right place! It’s a couple of mm lower than where it should be, which means he would in fact be around 25th percentile which isn’t worrying as he was around 30th on the 20 week scan. I have another scan in two weeks so will see what they say. But checking the chart has really reassured me, along with all your stories, thank you all 😊

@FlyingHighFlyingLow, @Cressie2 talk about an imperfect science!

Similar happened to me: 43rd at 20 weeks then 11th at 28 weeks. I queried it because I was worried and I think (if I remember accurately) they said it was because at 20 weeks they use a generic centile system based on whole-population, whereas in the third trimester they start to custom fit it against your own personal weight and height as a parent, as well as the centile of any previous children you’ve had. I am still not sure why this would be the case, but I’m sure that’s what I was told.

My baby remained 11th centile until 36 weeks when she suddenly grew and was born at 25th centile, perfectly healthy!

good luck with everything x

ahh this is why it's so hard to be certain about these in utero measurements! It's only a few mm out or incorrectly transcribed and suddenly everything can become very concerning when actually it's fine. It really isn't an exact science.

My first baby was similar to yours in that her 20 week scan was all 30th-50th percentile, but my fundal height started plateauing from about 32 weeks and I had a few growth scans. They said she was around 10th percentile and that if I wasn't already having an ELCS for breech presentation they'd have made a plan to get her out early. She was born 6lb 4oz so between 10th and 25th percentile (not sure exactly) and still tracks along that curve for weight and height at age 5. Think it's just the way she's built tbh. She was wedged deep in my pelvis so I wonder if that's why my fundal height wasn't changing.

A friend of mine had the absolute fear put in her that her baby was teeny tiny and not growing, very serious IUGR, she was signed off work at 34 weeks for daily monitoring and it was a really stressful time before baby's early delivery. Turns out she was a perfectly normal weight, 7lb+ and if she'd gone to 40 weeks she'd have been even bigger. No clue how they got it so wrong.

I had this and baby ended up being born 6 weeks early by planned caesarean. He was 3lb 6oz. I also got post partum pre eclampsia. It was all unbelievably stressful, however it all worked and out and my son is totally fine now.

It’s good they’re monitoring it and you can have another can to double check the stats. Even if your baby does need to come early, it’s better to know.