All about Twins and Twin Pregnancies!

Today, I wanted to write about twins (and this can apply to other multiple pregnancies).

I have a friend on FB - won't name names or anything - but she is pregnant with twins - so exciting!

I also started reading a book about a mother pregnant with Quads - yes that is four babies. In this book, the mother is even pressured to terminate 2 of the quads - but she refuses - and they all come out just fine. She actually goes to a special hospital far from home and stays at a Ronald McDonald house near the hospital till she goes into labor around 31 weeks - she has them by C-section and they all come out OK. She has 3 boys and a girl. The book title is Arise and Shine by Julianne Kirkland.

OK, so what is a twin pregnancy? How many types of twins can there be anyway?

Identical Twins:

"The National Library of Medicine says that monozygotic, or identical, twins are conceived from one fertilized egg. This egg separates into two embryos after it has begun to divide. These two embryos develop into two babies."

Non-Identical Twins or Fraternal Twins:

Just what it says - the twins do not match and can be girl/boy twins for instance.

A possible third type:

Polar Twins: Traditionally, the science around twins has taught that identical and fraternal are the only two types. But a third type might exist, called polar body or half-identical twins.

Though this has never been confirmed, a research review from 2016 suggested that a third twin type would explain why some fraternal twins look so similar.

After the ovaries release an egg, the egg can split into two halves, the smaller of which is called a polar body. This polar body contains all the chromosomes necessary to join with a sperm to create a baby. But since it usually contains very little fluid, or cytoplasm, it’s often too small to survive.

It’s possible, though, that a polar body could survive and be fertilized. Meanwhile, the larger half of the original egg could also be fertilized by a separate sperm. The result? Polar twins.

Polar twins share the same chromosomes from their birthing parent, but they get different chromosomes from their non-birthing parent. This is because they’re created from a single egg but two separate sperm.

For this reason, they may or may not be assigned the same sex at birth, and they may look very similar but not exactly identical." From this article: https://www.healthline.com/health/pregnancy/types-of-twins#third-type


Another style of twins - called "Mirror Twins":

Mirror twins are exactly what they sound like! These twins are actual mirror images of each other. This means that:

  • Their hair may naturally fall in opposite directions.

  • Their teeth may grow in on opposite sides of their mouths.

  • They may have birthmarks on the opposite side of their bodies.

  • They also usually have different dominant hands.

What causes this phenomenon? In a typical identical twin pregnancy, an egg splits during its first week after fertilization. But in a mirror twin pregnancy, the egg splits 7 to 12 days after it’s been fertilized — long enough for the egg to have developed a right and a left side. Source again: https://www.healthline.com/health/pregnancy/types-of-twins#unique-identical-twins


Conjoined twins are a rare twin type in which the two siblings are physically connected. Typically, conjoined twins are joined together at the chest or abdomen, but this varies. Some conjoined twins are connected to a greater extent than others. Most share at least one vital organ. Though physically attached to each other, conjoined twins are two individuals. They have unique thoughts and their own personalities. https://www.healthline.com/health/pregnancy/types-of-twins#unique-identical-twins


Besides types of above twins - there are twins who share a placenta or have their own individual one, etc.

Here are the types of placentas and twins:

Dichorionic Diamniotic -­ Two placentas, two amniotic sacs, two babies.

Monochorionic Diamniotic­ - Single placenta, two amniotic sacs, two babies. You will have one large placenta that can sometimes be peanut shaped.

Monochorionic Monoamniotic­ - One placenta, one amniotic sac, two babies. Commonly referred to as "momo" twins. This type of twin pregnancy is considered high risk. Because of the umbilical cord insertions points, it is unlikely that both babies would survive a vaginal birth. Momo twins are usually delivered via c­ section between 34-­36 weeks. https://www.placentalsg.com/post/types-of-twin-placentas

So, if you are a doula and helping with a twin pregnancy - we hope this article informs you a little more about what the various types are. If you are a mom expecting twins - congratulations! We may do an article about breastfeeding in near future and look at that for tips on breastfeeding twins. We hope you or anyone pregnant with twins will enjoy reading this article and getting a little more information!

This article is written by Julie Larsen with source quotes above - I am author of www.doulamoney.com/blog - thank you.


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