How accurate is gender on 21 week scan (Kings)?

[Thenadish]

We had our 20 week scan yesterday at 21 weeks at Kings College Hospital and wondered how accurate their assessment of gender is at this stage?

We didn't see anything(!) and are first time parents so have no prior experience of the accuracy of this.

Google seems to throw up opinions which vary by country and imply it's down to the skill of the assessor / person scanning. I wondered if anyone else was at Kings and how accurate their prediction was?!

Kings is one of the leading foetal medical centres in the world, and has very up to date equipment.

If they said they were sure, I'd be quite comfortable taking that as more than a 50/50 guess. You're not trained ultrasound technicians, so you may not have seen what they did, or recognised it for what it was.

Sometimes however the view is not great because the baby is not being cooperative. In this situation they'll usually say 'we think' rather than telling you it IS a girl or a boy.

At 21 weeks a sonographer should be able to tell fairly accurately as long as the baby lets them see! If they were confident to say 'it's a ...' Then they were sure. If it was a 'we think' or best we can tell them they weren't %100.

I was told my sons sex at a scan at 16 weeks so I'd think 21 weeks will be accurate

I would imagine they will be getting it right the vast majority of the time TBH.

Medical professionals tend to stop short of telling you anything is "definite" don't they? So I would expect them to say something like "it looks like a boy" or "it's likely to be a girl".

Unfortunately, saying a baby's definitely one sex or the other before birth leaves them open to potential litigation in this day and age.

That said, most people who find out the sex of their unborn baby are getting the correct answer .

By 21 weeks, the sonographer will be examining the baby in quite fine detail, looking at things which are quite small and deep within your baby's body, like blood vessels and heart valves. If they can see those clearly, I imagine they'll be able to quite confidently make out external genitalia!

If the sonographer didn't say they were uncertain, I'd personally expect it to be 90%+ accurate.

Thank you all! She didn't show us we had other concerns to investigate first and then at the end she said "oh do you want to know?" And when we confirmed and she told us I asked her how accurate she was and her reply was "I've seen enough of them/ I've been doing it long enough" - words to that effect...

Then that's about as confident as you're going to get!

Do you want to tell us the sex? Or are you keeping it private?

It's staying a secret! I have no problem sharing but DH is anti and only wanted to find out if we keep shtum....I agreed....

Had all my scans at Kings. They are very, very good there. It would be a whopping surprise if baby now turns out to be the other. Congratulations

Oh and I couldn't see anything on the scans either.

On my 20 wk scan for my first, I couldn't see anything. On my 20wk scan for this one we had an extremely clear view - to the extent that she showed us and asked if we could guess what it was (very obviously girl parts)!

Awww thanks guys!

If it's a girl it can be harder to feel confident in the answer because there is little to see - only the small three little lines like a burger (! but that is how it was described on other forums for me). If it's a boy it does tend to be more obvious. Usually you will be looking at the groin area from a strange angle so unless you have previously googled gender pics it can be harder to recognise what you're looking at.

At our 20 week scan the sonographer said 'probably' a girl because of absence of a penis, however at the angle we had the baby's groin was never firmly in position so it was difficult to tell for sure. We booked a short gender scan elsewhere for a week later and it was much clearer and they had the time to go through it.

At a regular 20 week scan they don't always have time to spend a while on gender.

I have my scan at kings on Thursday I will be 12+4, however I did have one last Monday but baby was measuring behind my dates hence why I have to go back. When I sat down the lady asked me if I wanted to find out the sex. I thought I was to early they said they can not tell for definite but will have a look. I was to small anyway only 11+1 but if they was going to try at 12 weeks I would say 21 weeks would be pretty accurate. As someone said earlier kings have the most advanced equipment within the country atm so I would be assured of this if they told me the sex.

I wish everyone the best with their pregnancies and congratulations I can not wait till I reach 21 weeks this first trimester has been a rollercoaster.

I went to Kings at 13+5, they are renowned.

We got told, the 'potty' shot we have is hilarious. No denying it's a boy!

Good luck with everything.

Potty shot! Haha love it!

The left thigh is in shadow but it's as clear as day

Apologies in advance to those that are easily offended by bits and bobs

Ahahahaha that is brilliant!

I had all my scans there and can say they were very accurate. Was told I am having a boy at 20 weeks scan and been confirmed at 36 weeks scan aswell but to be fair I could totally see a willie and testicles myself. One thing I did notice is they don't tell you unless they are 100% sure.

Good luck

Just an update ladies I had my scan on Thursday 13+4 weeks and they guessed girl so we will see if their so accurate so early :)

That's lovely Keys. Hope you are feeling better. Good luck with the rest of it.

Girls are brilliant (and bossy) I'm looking forward to what dynamics a boy brings.

Just as an FYI we had another growth scan at 33 weeks and saw the bits for ourselves and they were absolutely accurate at the initial San for those who wondered!

Kings told us gender at 13 week scan, then different sonographer confirmed it at 22 week scan!

Didn't have that with first DC at another hospital, kings must be pretty accurate I guess