Are Mongolian blue spots an unknown thing?

[Mrsknackered]

Both of my DS's have Mongolian blue birthmarks. DS1 has a completely blue bottom and DS2 has a blue bum cheek and at the top of his spine, a circular blue spot the size of a 2p.
They are noted down in their red books.
At swimming last night, a lady was sitting near us in the shallow end and kept giving me a funny look. She then said, 'think you've been holding wee man a bit tightly!' So I was like 'sorry, what?' And she pointed at his back and said 'that's a nasty bruise for such a young bubba!' (DS2 is 5 months)
I got really embarrassed as I can be a bit wimpy and awkward and explained it's a birth mark but she just kinda 'mmm'ed me!
I felt awkward after and wondered if others had noticed it too and also thought he was bruised :(
Are they not a known about? Should I be making nurseries/schools aware of their birthmarks?

Second AIBU of the week! What's happening to me

My sibling is married to an asian, and yes, they had a child with a blue bum. It really was quite blue.

Many people don't know about them. They had to tell nursery, childminders, schools etc about them.

dd had them, we have no idea which bit of her ancestry it came from.

It wasn't until I was on mn that we realised what they were. Various midwifes and health visitors would look in puzzlement and suggest that they were from her car seat bruising her.

show Apparently 1-10% of Caucasian babies have them. 75% of Asian and African babies have them. Interesting. I didn't know white babies got them at all

Thanks for the education never heard of them!

I have never heard of this before, and having just googled, I agree that some of the smaller marks do look just like bruises so I would have probably assumed that out of ignorance. The bigger marks look a bit more 'birthmarky' but still quite unusual.
Lots of pictures of lovely squidgy babies with blue bums though! That's made me smile

DS1 had one at the top one side of his bottom that lasted a good few years. DS3 also had one which was fainter and I think gone at around age 1.

I'm pretty sure they're common knowledge and were also mentioned in the pregnancy and birth/newborn book I had when I was pregnant!

I only know of them because a woman in an online mum's group mentioned her ds has one. I haven't seen it and don't know if i would recognise one irl.

SoulAccount yes sounds racist to me. I hadn't even thought about the paternity aspect but it's a good thing your brother is aware of your racial heritage as some dad's might not be and it could have caused issues! I'm glad he mentioned it on the feedback form. What a thing to say though!

My eldest DD had 2 (mixed Asian/ British) and while the biggest one disappeared she still has one behind her ear and she is now 12. I admit I hadn't heard of them before she was born.

Both my DC have them but I'm Chinese. Midwives and GPs all knew and had written it in their red books. I think upthread it has been mentioned it's in their training. But nursery definitely asked if it was a birthmark. They didn't suspect brushing. We just have to explain what it is.

Wish I'd photoed their bums now as I can't even clearly recall their appearance but it never occurred to me at the time!!

I know about them only because when I was nursing, two parents were falsely accused of child abuse. They were treated dreadfully by social services and it took some time for them to be cleared of doing anything.

Dt1 had one on her side. Dt2 had a strawberry naevus in the same place. We're of mediterranean descent. We did let folk know because it seemed nobody knew what the hell it was apart from me and HV. This was 20 years ago, thought it would be better known by now, but obviously not.

I was told about this by a friend who taught primary, about forty years ago. When I mentioned it in my own teaching, in secondary, about twenty years ago, I was told it was 'rubbish'. I'm interested to see it mentioned here.

There's a few threads on here about them.

My DS has one, it's faded quite a lot but still visible at four. I've made sure it's on his nursery notes as it does look like a massive bruise. I can remember being horrified when I first saw it - thought I'd been holding him too tightly! Then my mum told me I'd had one too.

Never heard of them!
Just googled, I'd probably think it was a bruise if I saw one.

I am a tea and we are made aware of them as part of our child protection training. This is only because a member of staff has a child with it though.

I'm not a tea. I'm a teacher!

Me & DH are white, no known Asian ancestry. DD has a faint blue spot at the base of her spine. I'm not worried about people thinking injury (it's clear it's not a bruise) I'm worried about people thinking infidelity! Ha. She's got a darker skin time than us two but has my eyes & her dads everything else

I've heard of them but the ones I've seen are only small 5mm ish ones. I didn't realise they could be so big.

I didn't know white people get them either. I miss dd's blue bum!

ShowofHands same here, DD2 was born with quite a large one at the base of her spine, no Asian heritage afaik on either side.

I'm v glad it was DD2 and not DD1, seeing as they both have brown eyes, and XH and I both have blue eyes. I think brown eyes from two blue eyed parents AND a MBS could have lead to some fairly hefty questioning from XH