13 weeks - twins different sizes

[ivfdreaming]

So I'm having fraternal twins (IVF) was we think boy/girl based on NIPT results!

One twin has consistently measured bigger than the other. At about 13 weeks the big one is now measuring ahead of my original dates and is approx 6 days larger than the smaller (which whilst smaller is measuring bang on to my original dates)

Is this normal??? What was the age gap difference in your twins during pregnancy??

I think it's fairly normal that early on, being so tiny. That 6 days difference will be literally millimetres! At my 7 week scan, DT1 was 1 day ahead of DT2 and at 13 weeks it had increased to 3 weeks ahead, but by 20 weeks they'd switched and DT2 was the bigger twin (and has been ever since!)

Sorry, 3 days ahead - not 3 weeks!

@PowerslidePanda

Thankyou for your reply! The worrying never stops does it! Two babies = twice the worry 🤣
I've lost 6 previous babies before these twins albeit at an earlier stage in pregnancy - I thought once i got to 12 weeks I'd worry less but now I'm finding other things to worry about until the 20 week scan! 🤣

Gosh, what a history! Very sorry for your losses But yep - the worrying never stops (including once they're out!) Just wait til you're counting kicks and trying to figure out which one is moving But they take good care of you with a multiples pregnancy too.

Mine have been measuring a week apart from the start - in fact at my 7 week scan the little one was a week and a half behind! The latest scan they were 12+2 and 11+2. It's been causing me anxiety since the beginning. Like you I was hoping the anxiety would be lessening a bit as the pregnancy progressed but it's double to worry about! I've had recurrent miscarriages and these two a were a huge surprise! Xx

(Mine are also fraternal by the way) x

@JennyMY

Congrats on your twins too! I've been reading that size difference early on especially with fraternal isn't so bad - it's worse if they share sacs/placentas - also trying to up my protein as read that helps too 🤞🤞

@ivfdreaming Congrats on yours too - how exciting to know the sex!
Yes, my midwife did say at least that as they're not identical it won't be TTTS. As yours are IVF, I'm presuming they'll be dating from the smaller twin who is measuring spot on? Mine unfortunately are being measured from the bigger twin (which I know from my dates is correct) but it means the little one is at times falling off the bottom percentile which looks far worse than saying a week off! 😕
I'm seeing my consultant on 7th Sept so we'll see how things are then. Best of luck with your little miracles too xx

One of mine (MCDA) was 20% smaller at 12 week scan. Sonographer not at all concerned. They’ve evened up as pregnancy has progressed (now 28 weeks), the one that was smaller is now very slightly bigger, but negligible difference.

Hi! I’m 17 weeks pregnant with twins - believed to be fraternal, separate sacs and placentas. Mine were about a week out in size at about 7 weeks when I had an early scan - sonographer was unconcerned. They closed the gap at 12 weeks and at my gender scan at 16+4 we had one twin spot on and another measuring a few days ahead.

@xbambi - Your post just reminded me of something that I didn't find out until after I'd given birth, so just posting it for general info... A significant size difference between DCDA twins can apparently be an indication that they're identical, not fraternal. No idea why (since TTTS can't come into play), but the difference in birth weights for my DTs was 1.5lb and sure enough, they were actually identical.