Active discussions

Please or to access all these features

Talk
Antenatal tests

Get updates on how your baby develops, your body changes, and what you can expect during each week of your pregnancy by signing up to the Mumsnet Pregnancy Newsletters.

Original poster

BABY HEAD BELOW 3RD PERCENTILE

16 replies

Ramyxx · 23/10/2023 19:26

Hi, I am looking for your experiences with baby head measuring small at 20 week ultrasound.
I went for my 20 week scan and was told baby head is below the 5th percentile. I was referred to FMU and was scanned by them the day after who have said everything appears to be normal apart from baby head being below the 3rd percentile.
They offered me an MRI - which I have accepted and have on Thursday.
The FMU consultant said after completing the scan the most likely cause is baby is small and petite BUT there are other possible causes like, chromosome abnormalities, infection (been tested for infection and came back neg) or genetic issues. He said as everything else he checked was normal and within normal range he thinks most likely just small but can't be sure hence the MRI.
He also offered me an amnio, which I have refused for the time being.
Has anyone else experienced this and what was the outcome?
Thank you in advance!!!!!

OP posts:
Original poster
Ramyxx · 23/10/2023 19:28

I would also like to ask, when did you get your results from the MRI, I have another appointment with my FMU consultant on the 15th November. Will they make me wait until then for the MRI results? Or will they contact me sooner regarding them? TIA x

OP posts:
Outliers · 25/10/2023 09:46

Ramyxx · 23/10/2023 19:26

Hi, I am looking for your experiences with baby head measuring small at 20 week ultrasound.
I went for my 20 week scan and was told baby head is below the 5th percentile. I was referred to FMU and was scanned by them the day after who have said everything appears to be normal apart from baby head being below the 3rd percentile.
They offered me an MRI - which I have accepted and have on Thursday.
The FMU consultant said after completing the scan the most likely cause is baby is small and petite BUT there are other possible causes like, chromosome abnormalities, infection (been tested for infection and came back neg) or genetic issues. He said as everything else he checked was normal and within normal range he thinks most likely just small but can't be sure hence the MRI.
He also offered me an amnio, which I have refused for the time being.
Has anyone else experienced this and what was the outcome?
Thank you in advance!!!!!

My advice is to take the amnio. It's uncomfortable but only for a couple minutes, a few days later you'll have total clarity which will make the next 20weeks far far less stressful - whatever the results.

SiouxsieSiouxStiletto · 29/10/2023 07:23

Is there a reason that you've refused the Amnio @Ramyxx? I know that some people refuse because they want to have the baby even if they have genetic conditions but when we had a PG that needed investigation, we were advised strongly to take the tests.

Original poster
Ramyxx · 29/10/2023 07:30

Thank you for your response @SiouxsieSiouxStiletto, we refused the amnio as the consultant has said that she could just be a small baby as apart from the small HC, baby appeared normal and that we will hopefully have more information with the MRI results. If the MRI shows no problem with the brain there will be no need to have the amnio as the risk of MC will not be greater than the risk of baby. But if something is picked up then we will possibly look at having the amnio x

OP posts:
BekahK · 01/10/2024 13:30

Ramyxx · 29/10/2023 07:30

Thank you for your response @SiouxsieSiouxStiletto, we refused the amnio as the consultant has said that she could just be a small baby as apart from the small HC, baby appeared normal and that we will hopefully have more information with the MRI results. If the MRI shows no problem with the brain there will be no need to have the amnio as the risk of MC will not be greater than the risk of baby. But if something is picked up then we will possibly look at having the amnio x

Hello, I note it has been awhile since this post but how was your baby girl? I am going through something very similar atm.

Original poster
Ramyxx · 01/10/2024 14:12

@SiouxsieSiouxStiletto believe it or not from 20 weeks I was scanned every 2 weeks until the decision was made to be induced at 37 weeks. Each scan they said the same thing about baby girl head and that she'd be small. Baby girl came out with a normal head circumference and is completely healthy! She is small but I am small myself. She was born at 37.5 & weighed 6lb 1oz x

OP posts:
Original poster
Ramyxx · 01/10/2024 14:14

@SiouxsieSiouxStiletto I had the MRI which showed her brain was normal and because of that I refused the amnio. I said further tests could be done when she was born. She never needed any further testing x

OP posts:
Diamonds86 · 20/01/2026 17:19

Hi I’m going through something similar I am 18 weeks I had a private scan today where babys head measured at 16 weeks but rest of body 18 weeks I’m really freaking out - I’m wondering how much smaller was your baby’s head measuring?
did they say anything about head shape at all?

Original poster
Ramyxx · 21/01/2026 07:38

@Diamonds86 so I was scanned every 3 weeks, I was told my baby would be very small and that her head was below the 3rd centile. I was told to buy clothing for a very small baby as only expected to be around 4lb. This continued until the week I gave birth. My baby was born at 37+5, she was 6lb 1oz and head size was completely normal xx

OP posts:
Original poster
Ramyxx · 21/01/2026 07:38

@Diamonds86 they didn’t tell me by weeks, they only told me the centile xx

OP posts:
Diamonds86 · 21/01/2026 07:58

@Ramyxx Thank you yes when I look at report it say head below 3rd centile as well, but body normal size. Ok thank you that’s really reassuring thank you xx
i have a scan with a consultant today so hopefully get some reassurance xx

Original poster
Ramyxx · 21/01/2026 14:58

@Diamonds86, please let me know how you get on xx

OP posts:
Diamonds86 · 21/01/2026 15:56

Ramyxx · 21/01/2026 14:58

@Diamonds86, please let me know how you get on xx

Suspected spina bifida. (Due to smaller head size and shape) They were not able to scan spine to tell us exactly due to babies position - however will rescan at fetal medicine tomorrow :(

Original poster
Ramyxx · 21/01/2026 18:25

@Diamonds86 I am so sorry! I was with fetal medicine also. They suspected microcephaly for me. I have everything crossed for you and baby x

OP posts:
Original poster
Ramyxx · 29/01/2026 08:13

@Diamonds86how was your rescan with FMU x

OP posts:
Diamonds86 · 29/01/2026 08:15

Spina bifeda unfortunately 💔

New posts on this thread. Refresh page