Different sized gestational sac?

Hi there,

I'm brand new to this forum, but am I ever glad I found it. I just found out a couple of weeks ago that we're expecting fraternal twins. I'm almost 9 weeks along. We've had two ultrasounds and both babies had strong heartbeats and appear to be developping well. The only thing that puzzled doctors was that there was a large discrepancy in the gestational sacs of the two babies. At 7W5D, twin A's sac measured 9.5 weeks and twin B's sac measured 6.3 weeks. I saw two different doctors and neither one appeared to be overly concerned. They said that they see this sometimes and that they usually even out. But my doctor did give us an 8% chance of Vanishing Twin Syndrome because she wasn't sure why there was such a discrepancy in sac size. I've tried doing research on the Internet, but basically, I'm scaring myself!

Has anyone had anything similar and had a good outcome?

Thank you so much!

Jen

 

Welcome to TS :sign0016:

Dianna

 

I was under the impression vanishing twin syndrome happens very early, before the heartbeat is even seen - how many weeks do you have to be before you are past the "vanishing" threat?

 

QUOTE(DblOsbornes @ Nov, 03:02 PM) [snapback]502458[/snapback]
I was under the impression vanishing twin syndrome happens very early, before the heartbeat is even seen - how many weeks do you have to be before you are past the "vanishing" threat?


My RE told me it could happen up until 12 weeks. In fact, he said there was a 10% chance until that point.

To the OP: Welcome. I'm sorry I don't have information for you to answer your question. I hope the little one will catch up in size.

 

First of all - welcome!!! You came to the right place for suppport, everyone here is wonderful!

At my first ultrasound @ 10 weeks, the sacs were measured about 8 days apart. At the next u/s they were a few days apart, and the next u/s they were the same. I was getting u/s every month at that time, then every week for the last 2.5 months. I was also concerned about the "vanishing" threat but my peri didn't seem alarmed.

I didn't do too much research because I didn't want to worry until I knew there was a definite reason to worry. The other thing to remember is that ultrasounds are only as accurate as the machines and the person who is doing the measuring.

Keep in mind that they are measuring something very small so that the slightest difference is amplified, technology has come a long way but it still has its limitations. I would only worry if there was a huge change in the heartbeats or if one baby was not increasing in size. I know it is hard, but try not to worry too much! Keep us posted on your progress.

 

Hi and welcome to TS!

At our first 3 u/s our girls measured 9 days apart. But by the time I was out of my first trimester, they were both the same. Good Luck

 

When i found out i was pg with twins (at 17 weeks) They always measured about 2 weeks apart.. Even now my little girl is tiny compaired to her brother..

 

Oops - double post!

 

Thanks so much ladies for your responses! They have reassured me somewhat. I guess what still confuses me is that the babies themselves are measuring almost the same size (2 days apart), but their sacs are what are so different. Is that considered the same as one baby measuring bigger than the other? We had 2 ultrasounds 1 week apart to make sure that both babies were continuing to develop and they each developed exactly a week, so the doctor said that was a really good sign. And they both had good, strong heartbeats. I guess what I really need to stop doing is researching things on the Internet!!

If anyone else has had a similar situation, please feel free to continue sharing - it's very reassuring as this is the only place I tend to hear positive outcomes about discrepancy in sac sizes!