Statistics About Twins and Multiples

Posted on 17. Feb, 2007 by Susan Heim in Loving & Living with Twins & Multiples

About 126,500 babies are born in the U.S. each year as part of twins or more, to approximately 63,000 families.

Fifty-three percent of all twins are born prematurely (before 36 weeks).

Seventeen percent of women pregnant with multiples develop pre-eclampsia.

Sixty-four percent of multiples are born at low birth weights.

In-vitro fertilization leads to multiples in approximately 30 percent of cases.

According to Hellin’s Rule, formulated in 1895, spontaneous (naturally conceived) twins occur once in every 89 births.

In 2001, 3.1 percent of all U.S. births were twins. The rate was roughly half in Europe. In the United States, one in 50 people is a dizygotic (fraternal) twin. One in 150 is a monozygotic (identical) twin.

If a woman has already given birth to dizygotic twins, she has a 4 times higher chance of conceiving another set of twins—one in 3,000 births.

A woman who is a dizygotic twin has a 1-in-17 chance of having a set of twins.

The fertility drug Clomid increases the chance of having twins to 1-in-10.

Approximately 70 percent of all twins result from fertility treatments.

African-Americans are more likely to conceive twins than Caucasians. Asians are less likely to conceive twins.

Women between the ages of 35 and 39 are more likely to conceive twins.

The more children a woman has, the more likely she is to have a set of twins.

Taller women conceive twins more often than shorter women.

Armadillos almost always give birth to monozygotic quadruplets. One type of armadillo often produces monozygotic octuplets.

Conjoined (Siamese) twins result from the egg splitting near the end of the second week following fertilization.

Identical twinning is 9 times more likely to happen if a woman becomes pregnant while breastfeeding another newborn.

Some scientists believe that women who consume more milk have a greater chance of having multiples because she is ingesting more insulin-like growth factor (IGF), which is commonly fed to cows to increase their milk and beef production.

About 25 percent of identical twins are mirror-image twins.

About 95 percent of all multiple births in the United States are twins.

Thirty-four out of every 1,000 births in the United States are multiples.

Between 1980 and 1998, the rate of triplets and higher-order births in the United States increased by 400 percent.

A woman has a 1 in 65 million chance of conceiving identical quadruplets.

The time for an egg to split into identical twins is very short. If the egg doesn’t split into two separate but identical eggs within the first 14 days after conception, it never will.

The record for the number of fetuses in the human womb at once is 15.

For every 400 sets of fraternal twins, one set will be made up of twins who have different fathers.

About 50 percent of twins are delivered by Caesarean section.

Women who eat meat or dairy products are 5 times more likely to have twins than women who are vegans.

Identical twins are more likely to be female than male, especially if they are conjoined.

Monozygotic twins are more likely to miscarry than dizygotic twins.

Since 1980, the number of triplets has increased tenfold.

Twins at birth are hospitalized twice as long as singletons, and medical costs are three times higher during the first five years of life compared with singletons.

Triplets are at higher risk for cognitive delays during the first two years of life.

Medical costs for a triplet pregnancy are estimated at $200,000.

About the Author

Susan M. Heim is a writer and editor, specializing in multiples, parenting, women’s and Christian issues. She is a former Senior Editor for the bestselling "Chicken Soup for the Soul" series. Susan's books include "It’s Twins! Parent-to-Parent Advice from Infancy Through Adolescence," "Twice the Love: Stories of Inspiration for Families with Twins, Multiples and Singletons," "Oh, Baby! 7 Ways a Baby Will Change Your Life the First Year," and the upcoming "Boosting Your Baby's Brain Power" and "Chicken Soup for the Soul: Twins and More." Susan's articles and essays have appeared in many books, magazines and Web sites. She is a member of the National Association of Women Writers and the Southeastern Writers Association, and has a degree in Business Administration from Michigan State University. Susan lives with her husband and four sons (two teenagers and twin preschoolers) in south Florida.

See All Posts by This Author

Subscribe to our RSS Feed

Bookmark

12 Responses to “Statistics About Twins and Multiples”

Gary Pollak

25. Aug, 2007

Perhaps you could clear up a question that we have been debating. One of us claims that twins cannot be produced on the first pregnancy. There was either a miscarriage or an abortion prior to concieving twins. Is this true or false?
Susan M. Heim

06. Sep, 2007

Gary, this is false. Twins can be the result of a first pregnancy or any pregnancy. I’m sure there are plenty of mothers who can tell you that they never had a miscarriage or abortion, but their first children were twins!
noorul

21. Jan, 2008

Susan, I’m curious about one thing. I’m 24 years old and don’t have any baby yet after a miscarriage and molar pregnancy. Do you think I have any chance to conceive quadruplets according to my age and the experiences I had? If I dont, do you have any suggestion on what I should do to conceive multiples coz I really want to deliver identical quadruplets (damn it!).
Susan Heim

24. Jan, 2008

The conception of identical quadruplets is extremely rare. According to Dr. Tom Key of Great Falls Hospital in Calgary, Alberta, the chances of giving birth to identical quadruplets is about one in 13 million. Dr. Jamie Grifo of the NYU Fertility Center says there are less than 50 sets of identical quadruplets. There is no way to cause this to happen. Even with fertility treatments, you may increase your chances of conceiving fraternal quadruplets, but not identical quadruplets. Remember that a pregnancy with multiples is considered very high-risk, especially with quadruplets. I would caution against attempting to conceive multiples.
Fred

24. Jan, 2008

What are the chances of a non identical twin girl having a twin baby?
Susan Heim

24. Jan, 2008

A woman who is a dizygotic (fraternal or non-identical) twin has a 1-in-17 chance of having a set of twins. This is most likely because she may inherit from her mother the tendency to ovulate more than one egg during a cycle, increasing the chances of conceiving fraternal twins.
me

05. Feb, 2008

I was wondering….My first pregnancy resulted in fraternal twins (boy/girl) there is no trace of twinning on either side of my family and was wondering what my chances were getting pregnant again. We are looking to start trying and was wondering what the odds are we would conceive twins again.
Susan Heim

05. Feb, 2008

Even though there is no sign of twinning in your family, if you already had a set of fraternal twins (conceived naturally, not through the use of fertility treatments), you have a 4 times higher chance of conceiving another set of twins. That’s most likely because you have the tendency to ovulate more than one egg during a cycle. So, if you did it once, you might do it again!

Susan Heim’s last blog post..The Kids with Daddy
Teddi

23. Nov, 2008

Susan, I have a question. I’m 20, pregnant with my first “spontaneous” child and have a BMI of 29.5, I think. (I read that overweight women are more likely to have twins/multiples.) The father is a monozygotic twin and I don’t think that his mother used any kind of fertility drugs or in vitro. My aunt on my mother’s side has had triplets, and my grandmother on my father’s side has had twins, I think. She also had a son that had a tumor recently removed that had teeth and hair. (The doctors said it was most likely an absorbed twin.) I know nothing about my mother’s parents or family because she was adopted. At 9 weeks I went to my first dr appt and although I had lost a pound or two since finding out at 4 weeks, my stomach was already starting to show. Now, at almost 11 weeks, I’m showing quite considerably.

My question is, knowing a little bit about my family’s birthing history and the history of the father, how likely do you think it is that this pregnancy is a twin/multiple?
Susan Heim

23. Nov, 2008

Hi Teddi,
The fact that the father is an identical twin shouldn’t influence whether you have multiples since, as far as we know, monozygotic twins are just a fluke of nature and not caused by heredity. However, if there are a lot of fraternal (dizygotic) twins and multiples on your side of the family, it’s possible that some of the women in your family inherit the trait to ovulate more than one egg during a cycle, which increases the chances of having twins. However, looking “big” in the first trimester is not necessarily an indicator of twins. Some women may just have looser abdominal muscles, especially if they’re overweight, which will poke out more quickly as the uterus expands. The only sure way for you to know is to ask your doctor for an ultrasound. Twins should be detectable through ultrasound at 11 weeks.
Marie

29. Dec, 2008

What are the chances are a dizygotic twin has monozygotic twin girls? (This is my story!)
Susan Heim

29. Dec, 2008

Hi Marie,
Nobody keeps statistics on that kind of thing, so I’m not sure what the chances are, but I’m guessing they’re pretty slim! As far as we know, conceiving monozygotic (identical) twins is completely random, so the fact that you’re a dizygotic (fraternal) twin should be irrelevant. You just got lucky!
Susan

Susan Heims last blog post..Giving Thanks in November