Multiple Births: Symptoms, Difficulties & Types

Multiple Births: Symptoms, Difficulties & Types
Coming up next: Premature Births and Associated Complications

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:01 Types of multiples
  • 2:49 Risks of multiple births
Add to Add to Add to

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Lesson Transcript
Instructor: Heather Adewale

Heather has taught reproductive biology and has researched neuro, repro and endocrinology. She has a PhD in Zoology/Biology.

While the thought of twins or triplets may be exciting or intriguing, have you ever considered the difficulties that are involved in the birthing of multiple babies? Learn about the different types of twins and some of the complications that come along with being pregnant with twins, triplets, and other sets of multiple births.

Types of Multiples

Age and fertility treatments can increase the chances of a woman having twins.
Chance of Twins

Did you know that about one in every 30 babies born in the United States is a twin? Now, while these numbers may make it seem like the chances of having twins is pretty good, the average woman actually only has about a 3% chance of having twins. However, this chance increases to 5% if she is over 30 and increases to 25% if she is receiving fertility treatments.

Other factors that may increase your chances of having twins are a family history of twins (and by 'your,' I'm referring mostly to the females listening - sorry, guys). Even your race can influence your chances. For example, did you know that twins are more common in African Americans and Hispanics than they are in Caucasians?

And, while the chance of having twins in general has increased, the chances of having identical twins has remained pretty steady, at about 0.4%, or one in every 250 births. This increases to one in 8,000 for natural triplets and one in 729,000 for natural quadruplets - 'natural' meaning that no fertility treatments were used to help with conception.

Identical twins, triplets, quadruplets, etc. can be one or a mixture of two types: monozygotic or dizygotic. A monozygotic set of twins or triplets is when both or all babies come from one egg that was released from the mother's ovary and fertilized by one sperm. Somewhere during the process of cell division, the single egg splits into two or more identical sets of cells, and each of these sets develops into a baby with the same original set of DNA. If any of these sets of cells fail to divide completely, the result could be conjoined (or Siamese) twins. In these cases, the twins often share some skin and portions of one or more internal organs.

Dizygotic twins or multiples, on the other hand, come from two or more separate eggs, each with its own, unique set of DNA, each egg being fertilized by a different sperm. This type is much more common, and about 70% of all twins are dizygotic.

Dizygotic twins account for the majority of all twins.
Dizygotic Twins

Risks of Multiple Births

While the concept of being a twin or having twins may sound exciting, the actual process of giving birth to twins or other sets of multiples can be a little problematic. Having to nourish and protect more than one developing baby can put extra strain on the mother's body, especially the physical strain placed on the uterus.

Risks associated with multiple births extend to both the mother and the babies. Some of these risks include:

  • Increased chance of premature labor: due to the physical constraints of the uterus, multiple births can lead to premature births and the complications that come with a premature baby.
  • One of these complications is lower birth weights. The less a baby weighs at birth, the higher the chance there is of other complications, such as breathing problems, digestion and feeding problems, and difficulty controlling body temperature. These are just some of the problems premature twins or multiples might face.
  • Abnormal presentation of one or more babies is also common. This means that one or more of the babies are not in the correct position for birth. If this is the case, and the baby doesn't turn on its own during the birthing process, the doctor may have to physically turn the baby to help it enter the birth canal properly.
  • This also means there is an increased chance that a C-section is required to deliver the babies safely. If the baby cannot be turned, or if the position for delivery puts its life at risk, then surgical removal of the babies from the mother's uterus may be required. This process is called a Cesarean or C-section.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account