** Twinning **

Prior to being a sonographer, I was only aware of 2 types of twins: Fraternal and Identical.

(But it's a little more complex than that.)

 

So Fraternal twins can be 2 boys, or 2 girls, or one of each. 

These twins are not identical, and are no more closely related than 

regular brothers and sisters are.

 

For Identical Twins, they can have a few different situations. 

They can:

1- be in their own individual sacs. and 

they can each have their own placenta, 

(this is called a di-di pregnancy)

or

2- they can each be in their own sac, but SHARE the SAME placenta,

(this is called a mono-di pregnancy)

or

3- they can be in the SAME sac and also SHARE the same placenta. 

(this is called a mono-mono pregnancy)

 

Each of these pregnancies are monitored by the doctor. 

You can expect to be getting a few extra ultrasounds. 

Be sure to get plenty of rest, and kick back and relax whenever you can! 

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** ok, that was the BASIC information on twins. Here is the in-depth explanation **

 

Let’s talk about twins, Bay-Be, let’s talk about A and B, let’s talk about twins, let’s talk about twins.

(If you know, you know.)   

 

So. Twins. 

So many different kinds! Who knew?!  

 

The above paragraph was the Beginners guide to Twins. This explanation is a little more in-depth, but will be repetitive in spots. However, we all learn the most effectively by repetition, so here it goes.

 

Let’s talk about Fraternal Twins first. 

Fraternal twins are twins that are NOT identical. It could be a boy and a girl. And sure, it could be 2 boys, or 2 girls, but those babies are not identical to each other, even if they are the same gender.  These 2 babies have their own amniotic sacs, and their own placentas. 

Ok wait, let’s back up. An amniotic sac is like… a studio apartment. It’s the baby’s very own place to call home. No roommates in there.  A placenta is what supports the pregnancy- gives nutrition, blood, and oxygen, -like a kitchen, so to speak. Going forward, we’ll use this analogy.  

So with the Fraternal Twin Pregnancy, each baby is in their own studio apartment, and each baby has their own kitchen. This pregnancy can be referred to a Di-Di pregnancy. (The word Di means 2, so there are 2 of each: 2 placentas and 2 amniotic sacs.) 

 

Now on to the more complicated stuff: Let’s talk about Identical Twins-

 

 These 2 babies, started as one solitary egg. The egg has then fertilized by one solitary sperm. And then the egg suddenly- for what ever reason- split in to 2 eggs. Remember, fertilization had already occurred. So these 2 fertilized eggs are completely the same. Identical.  

 

Let’s say that if the egg splits early on (with 3 days of being fertilized,) then each baby could potentially have their own amniotic sac and their own placenta. (Remember that means that they each have their own studio apartment and their own kitchen.) This is also called a Di-Di pregnancy. Remember that means 2 of each things: 2 placentas and 2 amniotic sacs. 

 

Now, if the egg splits later on, (between days 4-7 of being fertilized,) then each baby will be in it’s own sac, but they will share the kitchen. This type of twin pregnancy is called a mono-di pregnancy. (Mono means one.) So it means 1 placenta, and 2 amniotic sacs. 

 

If the egg splits later, (between days 8-12 of being fertilized,) both the babies are now growing in the SAME Amniotic sac, and share the SAME placenta. So back to our analogy: a studio apartment with 2 people living in it, sharing the same kitchen. This type of pregnancy is called a Mono-Mono pregnancy. (Meaning 1 placenta and 1 amniotic sac.) This is a high risk pregnancy, and your doctor will monitor you closely for the duration of your pregnancy. Don’t worry though- you are in good hands. The doctors know what they are doing. 

 

On very rare, infrequent situations, the egg splits after day 13. However, the egg doesn’t always completely split apart. Some of it may remained attached to the other egg. This occurrence results in conjoined twins. This means they are connected by a body part. They will require surgery upon birth to be separated from each other. This is also a high risk pregnancy.

 

I hope all this information was helpful to you!