Monochorionic Diamniotic Twins

If you are just stumbling on my blog because you googled about MoDi Twins – Hello! My girls are growing so well & turned 3 years old in September! I can’t believe it’s been that long already! If you have any questions at all or need someone to complain to – I’m all ears. Just shoot me an email & I’ll try to get back to you as soon as I can! ( I have updates on the girls as well if you’d like to read through those – they are on my Twins Page. Thanks so much for stopping by!

I have had many of you ask me questions about the twins….the reason for the early delivery, how I know if they are identical or not and the list could go on and on. I’m going to try and do a little “informative” post about the type of twins we are having and why we are more of a “high risk” than a twin pregnancy with fraternal twins OR twins with separate placentas.

What exactly are Monochorionic Diamniotic twins?
They are monozygotic (identical) twins that share the same placenta. (

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The low down on identical twins:
They are originally from one embryo that split into two. If the embryo splits very early on, then the twins are identical but have separate placentas and amniotic sacs (dichorionin, diamniotic). If the embryo splits a little later, the result is identical twins that share a placenta (monochorionic) but are in separate sacs (diamniotic). Very late splitting of the embryo is rare but can result in conjoined (siamese) twins, or two babies that have the same placenta and are in the same sac (monochorionic, monoamniotic). This type of twins is at highest risk of various complications of pregnancy.

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Why are they suggesting a cesarean section for your delivery even though you delivered both boys vaginally?
Because the girls share a placenta they are at risk of developing TTTS (twin-to-twin-transfusion-syndrom). They have both, thankfully, gotten past the “danger” stage and are both growing well, but with a shared placenta the girls will run the risk of developing TTTS even through a vaginal delivery. With the delivery through c-section this takes that risk away completely.

Why do they suggest taking the girls out at 36-37 weeks? Don’t they want them to gain as much weight as possible?
They suggest 36-37 weeks because of the TTTS. Once they are “healthy” enough to come out, they suggest taking them so they don’t ever have the risk of developing TTTS since it can be fatal. Yes, they do want them to gain weight, but having them healthy & a small weight is better than keeping them in longer than necessary and running the risk of developing TTTS.

What exactly IS TTTS (twin-to-twin-transfusion-syndrom)?
It is a complication of disproportionate blood supply, resulting in high morbidity and mortality. It can affect monochorionic multiples, that is, multiple pregnancies where two or more fetuses share a chorion and hence a single placenta. Severe TTTS has a 60–100% mortality rate. (wikipedia)

Currently the girls are showing no signs of TTTS and are both growing beautifully. They are still smaller than normal, but growing well. During our scan last week they also showed that each twin has the exact same amount of fluid in their sacs, which is also a huge plus. I have to get an ultrasound every other week to check on their growth, amnionic fluid levels & make sure the membrane is still looking well. Our last scan, the doctor told me that their membrane was “absolutely beautiful”. It just looked like a squiggly little line to me 😉 .

When are you due?
Oh goodness. I get this question asked all the time, and if I were a ‘normal’ twin pregnancy it would be so simple to answer. Here’s the gist of it:
I am technically due: October 17, 2012
Average time for twins to arrive is 35 wks which would make me due: September 11, 2012
Delivery of MoDi (MCDA) twins here in the UK is 36-37 wks which is: September 19-25, 2012
SO…..I tell people early/mid September. This way I’m covered from about 33 weeks. (which is very likely I’d deliver closer to)

I think that’s all the information I’ll load you with today. I hope I’ve helped you better understand this whole “twin” thing. ha ha.


 shaklee distributor


  1. says

    So fascinating! And I’m SO glad to hear that they are growing well and at the same rate. My twins are fraternal so we didn’t have these extra worries, but it sounds like everything is going smoothly. :) Strangely enough one of my boys was about 2 weeks behind the other in growth for the entire pregnancy so we wonder if they weren’t conceived on the same day, but we’ll never know.

  2. Angie says

    Very well explained! Now here’s another question….why not cloth diaper in the beginning?

    Oh and you’ve got a package being mailed today :)

  3. says

    I’m loving ready about your pregnancy! I am due October 21st, 2012, so we are on the same track, only I only have one blessing instead of two!

  4. says

    I’m loving ready about your pregnancy! I am due October 21st, 2012, so we are on the same track, only I only have one blessing instead of two!

  5. says

    What a wonderful blessing! God is SO good. Looks like our special package/packages will be arriving around the same time…
    I can’t wait! :)

  6. says

    Well, I learned a lot today. Sounds like you guys have done your research and have a good handle on what to expect during the delivery process. :) Know that we’re praying for you guys every step of the way!

  7. says

    Hi! I’m so glad I found your blog today!! I’m also due with twins!! I look forward to going back and reading more!!

  8. Niki says

    Thanks for explaining. I am crossing everything that everything continues to do well with the girls.

    {huge hugs}

  9. Jemma says


    Very well explained! I am currently 36 weeks pregnant with MCDA boys!  We have been watched very closely for TTTS too but they have both been growing well with no problems. They have both been head down for 10 weeks so our hospital is preferring a vaginal delivery for me and I will be induced  a week today! 

    Wishing you all the best – not long now! :-)) x

  10. Michelle says

    Hello my name is Michelle….I just found out that I’m having twins and they are monochromic diamniotic identical twins. I’m only 7 weeks and I am very nervous and scared. After reading your selection you have eased some of my fears and I thank you so much for that. I have a long road ahead of me:(

  11. Jennifer says

    So glad to hear that your girls are doing well. I stumbled over your blog because I’m having MoDi girls in early December (officially? Theoretically? I don’t know.) Never in a million years did I think I’d have twins. Thanks for the post.

  12. Kendra says

    Hello :) I have an identical twin sister, and we learned a few years ago that we are MoDi twins. We’re now 20 years old, but after listening to stories about our birth we knew this had to be the case. Our mom had been told by her doctors during delivery that, “They were in separate amniotic sacs, but they shared a placenta”. Back in Charleston, WV in 1993 this was a rarity and no one knew much about it. Needless to say, we are both healthy and happy with no health complications other than my younger twin being a little smaller and born with a minor heart murmur that grew over almost immediately. (And my mother gave birth to us vaginally, and while I came out perfectly fine, Kaitlyn was breeched and delivered vaginally as well.) It’s crazy to see how doctors are more knowledgeable about our type of twinnage nowadays. We made medical history in the hospital we were born in, but were also born after our due date which is rare for most twin births. I’m sure your twins are beautiful and healthy. They’ll share a bond that will be unlike any other relationship in this world.

  13. Berni Brimmage says

    Hi there, I have identical twin girls who are 6 (going on 16 with attitude!), they were also monochorionic diamniotic twins. I had a great pregnancy although I had to give up work at 24 weeks. The great thing about this type of pregnancy is all the special care and attention I received at the Hospital. I had scans every two weeks and really feel I got to know my babies before they were born. I had an emergency C-section after being in labour for 17 hours. My girls were born on July 31st 2007, healthy weights of 5 1 and 4 11. We stayed in The Great Western Hospital in Swindon (England) for a week and then we all came home together ! We now all happily live in the USA.
    It was great to read your blog !

  14. Rosa says

    Hi to all moms of twins. Twins are a double blessing! What a joy.

    I have 16 year old twin boys. We are just finding out now that they are identical, the membrane was diamniotic and dichorionic. My pregnancy was very healthy and i made it full term. I had a C section and that was great. NO pain. Boys weigh was 7.7 and 7.11. Big babies. I had the biggest tummy ever :) my husband tried his best to always make me feel pretty.
    16 years latter, I m still enjoying my boys. The teen years are challenging, we have learned to trust The Lord with all our heart . At the end of each day we still think that twins are the best thing ever!!

  15. Manu says

    I have triplet pregnancy with monochorionic diamniotic twins . My doctor suggested me to go for Fetal reduction of twins and continue with singleton .I don’t have much information about other option available for me . Please suggest or share some e-mail id’s or number who can help here ..

    Looking forward for replies


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