Mono/Di (identical) Twins Sono Weights

miragetdp

I'm 22 weeks with identical twin boys and have had an early anatomy scan and weekly sonograms because Baby B is smaller than Baby A. There are no signs of TTTS or any other abnormalities, just that Baby B is approximately 30% smaller than his brother. I know this is common with fraternal twins, but causes alarm with identical twins.

My question is, how much did your identical twins weigh at your sono(s)? Or if you've already had indentical twins, how much did they weigh at birth? My sono weights are listed below.

14 Weeks:
A: 4 oz
B: 3 oz
25% discordance

17 Weeks:
A: 8.67 oz
B: 6.03 oz
30.5% discordance

19 Weeks:
A: 11.78 oz
B: 8.11 oz
31.2% discordance

20 Weeks:
A: 15.63 oz
B: 10.26 oz
34.4% discordance

21 Weeks:
A: 1 lb 1.53 oz
B: 11.9 oz
32.2% discordance

caitdana

My Mo/Di twins weighted 1.8 oz and 2.3 oz at birth at 27 weeks. We stayed steady at 16% descrpency till about 22 weeks and it got dramatically more significant after that.

They thought it could be possible TTTS or IUGR. (At 27 weeks it turned out to be both).  I honestly would not obsess over their weights and discordances. I did and then later found out that it is really okay. 

The main concern is if the fluid is off balance (signs of TTTS) or if the babies stop growing all together (signs of IUGR).

iamnotyou

I don't have exact numbers as I'm not at home, but my girls had always been nearly identical.  One u/s showed one baby significantly larger than the other.  I had to come back a week later to measure again and they were back to a similar size.  I think they wanted my girls to stay w/in 25% of each other.  They were born at 5#11 and 5#14 and have remained w/in 2 or 3 oz for the past 2 years!  Hang in there. 

pea-kay

My coworker's wife had mo/di twin boys in May and they always had a similar discordance. Their MFM was sure something was going to be wrong with the smaller twin, but he was 100% healthy. Their fluid levels were always fine, he was just always smaller.

When they were born, A was 4'2 and B was 5'11.

Mrs_MBed

iamnotyou:

I don't have exact numbers as I'm not at home, but my girls had always been nearly identical.  One u/s showed one baby significantly larger than the other.  I had to come back a week later to measure again and they were back to a similar size.  I think they wanted my girls to stay w/in 25% of each other.  They were born at 5#11 and 5#14 and have remained w/in 2 or 3 oz for the past 2 years!  Hang in there. 

This has been my situation so far - the boys have been either within a day of each other or the exact same.  Last u/s (2 wks ago @ 16 wk 1 d) they were both measuring at 17 wk 1 day and 7 oz each.  I see the MFM tomorrow, so we'll see then if they are still measuring the same.  

 

miragetdp

caitdana: Their fluid has always been normal and they grow every u/s so I'm hopeful that the size difference is nothing other than one being a little piggy compared to the other, lol.

@pea-kay: Thanks for the positive reinforcement. My MFM (what does that mean, I'm assuming "specialist"), made me and DH feel like we should be prepared for a baby with some sort of terrible chromosonal abnormalities and so we kind of freaked at the first appt with her. Shortly after that we decided that we shouldn't be so worried and are just keeping high hopes for completely healthy twins. It seems like there are so many scare tactics, almost meant to force you to have unnecessary and COSTLY tests done, only to find out in the end (e.g. in your co-workers case) that there is nothing wrong at all. Oh, the stress! But it will all be worth it in the end.

caitdana

Be reassured with identicals their chromosome are nearly identical.  While in the NICU we had  genetic consult for my smaller twin. I was all concerned, but it was a teaching hospital and they said they had to rule out Turner Syndrome (almost everyday felt like a day on the set of House) but they knew she probably did not have it since my bigger, non-symptomatic identical twin did not have any flags.

 

Mrs. Alice

My mo/di boys started having about a 20% growth discordance at 22 weeks and they were also showing signs of TTTS.  Over the weeks the growth difference started getting farther apart and at 24 weeks baby A had absent end diastolic cord flow.  I was admitted for close monitoring and had u/s every other day check fluid levels, cord dopplers, and growth scans every 2 weeks.  I delivered at 28 weeks when his growth dropped to 7th percentile and he had reverse blood flow.  They weighed 2 lbs and 2 lbs 7 oz at birth.  Now there is more than a pound difference between them.  Has your Dr. done a cord doppler u/s?

ETA:  Thanks to the growth discordance math post I figured this out:  The u/s on the day they were born predicted A to be 1lb 12oz and B to be 2lb 10oz = 33% difference.  There was actually only an 18% difference between their birth weights and now there is only a 16% difference.

robynmoreland1

I had an ultra sound yesterday.  At 24 weeks A is 1lb. 11oz, B is 1lb. 8 oz.  Around a 6% discordance in weight.

miragetdp

Mrs. Alice:

My mo/di boys started having about a 20% growth discordance at 22 weeks and they were also showing signs of TTTS.  Over the weeks the growth difference started getting farther apart and at 24 weeks baby A had absent end diastolic cord flow.  I was admitted for close monitoring and had u/s every other day check fluid levels, cord dopplers, and growth scans every 2 weeks.  I delivered at 28 weeks when his growth dropped to 7th percentile and he had reverse blood flow.  They weighed 2 lbs and 2 lbs 7 oz at birth.  Now there is more than a pound difference between them.  Has your Dr. done a cord doppler u/s?

ETA:  Thanks to the growth discordance math post I figured this out:  The u/s on the day they were born predicted A to be 1lb 12oz and B to be 2lb 10oz = 33% difference.  There was actually only an 18% difference between their birth weights and now there is only a 16% difference.

@Mrs Alice: Thank you for the info. I will definitely mention the cord doppler u/s at my appointment tomorrow. I know they both have 3 vessel cords, and so far no signs of TTTS but it never hurts to check ALL possible issues. Thank you again.

 

@caitdana: Thanks for the reassurance. There's so much information out there its hard to find what applies to you.

erinruns

I have all of my weights at their u/s at home, but I think we were at a 25% discordance at 19 weeks.  Mine also showed signs of TTTS though.  When they were born, the MFM noticed that my placenta hadn't divided in half, it was more 2/3 - 1/3.  So my little one didn't have a ton of room, and her 2 vessel cord wasn't inserted correctly which caused a lot of the problems.  

miragetdp

Hey ladies! Went for an ultrasound last week and we are down to a 26% discordance from the previous 32%! I'm so excited! We had another u/s this week but they didn't do measurements. But our sono tech did measure each baby's foot and they were exactly the same length. I'm so happy!! Thank you to everyone for the positive support! I am feeling much better about my boys and the next few months of pregnancy!!

Side note: is there a way to get a notification when someone replies to a post you have written or replied on? I have just been checking randomly for replies, but it would be so much easier if I got a notification...

kiwi443

mirage - So glad to hear things are looking better for your boys!

At 23 weeks mine were 1 lb. 5 oz. and 1 lb. 4 oz.