One twin measuring 3-4 weeks behind

Hi I just joined this forum. I am almost 19 weeks pregnant with fraternal twins. Everything was going good with them (except for a SCH at 8 weeks and at 11 weeks my bloodwork came back screen positive for downs - the scan was good though and I refused the amino). Yesterday I had my anatomy scan at the peri and twin A looked good (except for a bit of fluid in her kidneys) but they had a very hard time trying to do the exam on twin B (the tech kept pushing me with the u/s probe and I had to keep turning from left to right). Finally after only doing half the scan on twin B she stopped and told me to get undressed for the cervix check. I asked her if she was going to finish the exam on baby B since we weren't even told the sex, etc and she said no the doctor would do it. When I was in the bathroom she told dh that baby B measured small. I do know the head was saying 15 something weeks - I didn't look at the abdomen or femur or any of baby A's measurements. I thought it was weird the head said a 15 week gestation age since I am in my 18 week but just assumed it was the u/s equipment. When the doctor came in he confirmed baby A was girl and had a quite glance at baby B then said baby B was 4 weeks behind (don't know why he said this when I saw the head was only 3) and that at this stage it is almost always a chromosomal issue and that we should do an amino to rule in or out a chromosomal problem. Now since the beginning of my pregnancy I have sworn I did not want to do an amino. These babies are a result of our 2nd ivf cycle - our first cycle resulted in a m/c at 8 weeks and we will likely not be able to do any more cycles because despite me just turning 31 my ovaries like to think they are 39 (these were the only 2 embryos we had so it is a miracle that they both continued to divide and implant). I told the peri I don't want to do the amino and then he started going on that if we don't that they will have to base the pregnancy on baby B and therefore take both babies at 24 weeks thereby putting baby A in danger of early delivery when baby B may not be viable anyways, while if they do the amino and find out baby B has trisomy 18 or 13 they could just ignore it and concentrate on saving baby A instead of trying to save baby B too. He went on about this for a good 20 minutes (I thought I would never get out of there unless I agreed to an amino) finally I said Look we can not make this decision right here right now and I would like to discuss it with my OB. He then said fine and made a followup appointment for me 3 weeks later (don't know why he is waiting so long - maybe because he is mad I wouldn't do the amino) and to call him if we do decide to do it.
I have been trying to research like mad, but unfortunately not finding much information out there about a baby measuring this far behind this early. Both babies were measuring the same up to this point and I just can't believe it is a chromosomal problem since it didn't appear baby B had any other problems besides just being a lot smaller. Another thing I wonder is maybe he was measuring smaller because he was hard to get (maybe he is behind baby A or has an anterior placenta - I don't know just that they were able to do the exam easy on baby A and I can always hear baby A clearly with the doppler while baby B is very difficult to find.)

 

Your peri sounds like a jerk; so sorry you had to go through all of that.

I'm certainly no expert, but one of my ID girls always measured two - three weeks behind her sister (our first U/S was at 20 weeks) and she was born healthy with no issues at 36 weeks. At first the peris and OBs I saw were concerned she had a problem, but then decided she might just have a cord that implanted near the edge of the placenta so she got fewer nutrients. Turns out, that's exactly what happened.

She was also wedged in the bottom of my uterus so they frequently had trouble measuring her. It seems like that could be a contributing factor to the size difference your U/S tech found.

If you want advice, I'd say to find another peri and get a second scan and a second opinion before you do anything more drastic. Good luck!

 

I'm so sorry you are going through all this.

I don't think you'll get definite answers anywhere until you do your follow up consult with the ob or get a second opinion.

While idril's post is encouraging, if I understand her correctly her twins were identical, not fraternal like yours. And I *think* substantial difference in size is more common in identical twins. Someone correct me if I'm wrong. You also need to take into consideration your nuchal bloodwork results.

You have a very valid concern you are facing. And while the doctor was insensitive he does make a valid point. Your future decisions about your babies can rely upon having definite information about their conditions. For one, some genetic defects are not compatible with life. Some have a very poor outcome, like trisomy 18. IMO you need to gather as much information you can to make an informed decision regarding next steps.

If you are reluctant to do the amnio I would absolutely suggest a second opinion. Maybe a 4d scan too or whatever non invasive tests your docs recommend. I would not want to wait for 3 weeks for the OB consult, try to get in earlier.

You are faced with a decision. You will want to make it as informed as you can be, either by doing an amnio or, if you choose not to do the amnio, to somehow get further testing done and more consults.

I hope everything turns out for the best for you and both your babies.

 

Oh I'm so sorry you are going through this. We have VERY similar stories in a lot of ways: I'm pg with b/g twins from our first (and only since we paid out of pocked) IVF. I also had an SCH develop at 8.5 weeks, which led me to be on bedrest for almost 5 weeks. When I went for my NT scan, the babies were not in the right position to measure...but they peri told me NOT to do the bloodwork b/c early pg bleeding and twins can skew the results to appear positive when they're not. Once we said we wouldn't selectively abort a baby no matter the results, they said we should be able to deal with any concerns at the anatomy scan. I don't know much about babies measuring differently, mine do measure a few days behind but that's it. I think a second opinion and maybe even a meeting with a geneticist would be in order. I do hope you get someone to walk you through this stressful time and not try to bully you into something that you don't want to do. Take care!

 

I'm sorry you even have to deal with this.

I went through IF tx too - so I understand where you are coming from. Here is my take:

You can always do an amnio later when the risk of m/c is lesser and the odds of a baby surviving are higher if it caused a problem. I was given that option with my first pregnancy when I had a trisomy 18 scare. I truly DO NOT like that your peri gave you such an ultimatum.

Was there any type of testing done earlier on in your pregnancy to check for chromosomal issues? A nuchal test of some sort- if yes, what odds were you given. Are there any other markers they see other than the size variance? These are things I'd ask. If it's just size, I think I'd wait and do the amnio a bit later.

But if the diagnosis of a trisomy issue doesn't change your mind about carrying the babies full term, I'd probably turn it down too. And that is your right. I would discuss with your OB, and don't hesitate to explore ALL of your options - don't feel pressured... these are your babies, and your body!

Best wishes!

 

My daughter is going through this right now please what was your out come.