A Brief Explanation

Just what are "monoamniotic twins"?


There are two types of twins in general, fraternal (which are considered genetic in that they run on the mothers side) and identical (which are spontaneous). Identical twins share 100% of their genes and occurs approximately 1 in every 250 pregnancies. Monoamniotic twins are always identical...here's why:


When the egg splits, one of the first things to form is the yolk sac. No one is really sure why, but the important question is whether there are two yolk sacs or just one. If the egg splits after the placenta has formed, then the two babies will share a placenta and and chorion (somewhere between 8-12 days after conception). This is what we mean when we say Monoamniotic Monochorionic (or MoMo twins).


This means that both babies share the same living space. They don't just share their house, they share a bedroom, bathroom, and playroom. While it is still possible even for a singleton to become tangled in his or her own cord, monoamniotic twins have to worry about becoming tangled in their sibling's cord, too. Cord entanglement is the number one risk in this type of pregnancy.


One other thing with monoamniotic twins is that I will be delivering via c-section, prematurely. The idea is to balance the outside risks (prematurity) vs. the inside risks (cord compression). MoMo twins are very rare. Occurring in only 1 percent of all twin pregnancies and are always the same gender.


We are very blessed to have the love and support from our family and friends. We appreciate the prayers and everyone who has listened to our worries and concerns and the time you have given us. If you have any questions about any of this, please feel free to email or call me (as Craig said, I am on bed rest...not because of the monoamniotic twins, but because my body is essentially 'full-term' for one baby and we need to do everything we can to keep me from going into pre-term labour).


Here is a diagram of what the two babies look like:


Here are the twins on the day of discover, December 29th, 2008 at 18 weeks 4 days:
-Lindsay