Statistics About Twins and Multiples

Statistics About Twins and Multiples

photo credit: sparkules

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.

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About Susan Heim

Susan M. Heim is an author and editor, specializing in multiples, parenting, women’s and Christian issues. Her books include "Boosting Your Baby's Brain Power"; "Chicken Soup for the Soul: Twins and More"; "It’s Twins! Parent-to-Parent Advice from Infancy Through Adolescence"; "Twice the Love: Stories of Inspiration for Families with Twins, Multiples and Singletons"; and, "Oh, Baby! 7 Ways a Baby Will Change Your Life the First Year." Upcoming books include "Chicken Soup for the Soul: All in the Family," "Chicken Soup for the Soul: Devotional Stories for Women," and "Moms of Multiples' Devotions to Go." 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 grade-schoolers) in Florida.

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  1. Gary Pollak says:

    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?

    • Vanessa says:

      This is false. Both my best friend and myself have and are having (myself) twins and it was our first and only pregnancy. Nither her or my self had a miscarriage nor and abortion prior to consieving twins.

    • I conceived fraternal twins, naturally, with my first pregnancy. I had never been pregnant before nor have I ever had an abortion or a miscarriage.

  2. Susan M. Heim says:

    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!

  3. 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!).

    • Get pregnant 64 million times!

    • Is this a joke?? Do you know how dangerous that is, and to wish it upon yourself and potential children is ludicrus.. You obviously need to do some more research. Women conceiving higher oreders of multiples like this DIE and lost thier babies, and here you are wishing for that!! Having twins myself, I absolutely HATE when ppl say, “oh I wish I had twins” or, “How did you do that” or “how can I have twins?” I think it completely demeans the hard work it takes for mothers of multiples to just get through the day sometimes.

  4. Susan Heim says:

    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.

  5. What are the chances of a non identical twin girl having a twin baby?

  6. Susan Heim says:

    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.

  7. 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.

  8. Susan Heim says:

    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

  9. 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?

  10. 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.

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

  12. 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!

  13. Jennifer says:

    Hi. My husband and I had to terminate my last pregnancy as we were expecting naturally conceived monoamiotic/monochorionic twins and one had a severe defect that we were told would definitely result in death of her and her sister (although she seemed healthy at the time). We terminated the pregnancy at 15 weeks, 6 days. I am 26 years old with a beautiful and healthy 2 year old daughter at home. I have just discovered that I am pregnant again (4 months after we lost our twins). Would I have a higher likelihood of conceiving another set of twins this time around? Please keep your fingers crossed for us!

    Thanks in advance!

  14. Susan Heim says:

    Hi Jennifer,
    Experts tell us that, as far as they know, identical twins are just a fluke of nature. An egg happens to split in two, so conceiving identical twins is not an inherited trait. Therefore, you probably do not have a higher likelihood of conceiving twins based on your previous pregnancy. It doesn’t mean it couldn’t happen, of course, but your odds are probably the same as any other woman’s. Good luck to you!

  15. Hi. I am pregnant with twins. Had an us at 7 and a half weeks indicating two heartbeats. I am 9 weeks today. Once I have made it to this point, what are my odds of delivering twins?

  16. Susan Heim says:

    Hi Stacey,
    Every twins pregnancy is different, so that’s something you’ll need to ask your doctor. You’re still in the crucial first trimester. I think the fact that he/she saw heartbeats is a very good indication but, of course, never a guarantee! But, hopefully, all will work out okay. If the twins and heartbeats are still present at your next check-up, then your odds have gone up that the twins pregnancy will continue. Be sure to take good care of yourself and follow your doctor’s orders as twins pregnancies are considered high-risk, and early delivery and bed rest are common. I wish you all the best!

  17. My daughter is 15 weeks with identical twins. One placenta two sacks. her last ultrasound was at 13 weeks and was to determine two heartbeats nothing else. She is not scheduled for another appt and ultrasound until 17 weeks and will then see a specialist at 18 weeks. How often should my daughter been seen as this is a high risk pregnancy……four weeks seems like forever. She is 23 years old and very healthy and physically fit and as of the 13 week appointment no weight gain but has a very small pouch which is not noticeable.

  18. I am 28 yrs old 5wks pregnant with my first. My husband and I had to see a fertility specialist. We did a round of Menopur shots. I produced 3 mature eggs that measured 22cm each. What are my chances of having multiples or that all three eggs took?

  19. My partner and I have had seven miscarriages, and are currently 11 weeks pregnant with twins.
    For obvious reasons we are on a very large amount of drugs to try to retain the pregnancy.
    At this point we are unaware of whether they are mono- or di-zygotic or chorionic.
    What are our realistic odds of actually carrying these two to a viable point?

  20. marrissa genie says:

    Hi, susan if i am a fraternal female twin and i am pregnant with my 2nd child with a bmi of 30.1 and 21 years of age and African American WHAT WOULD BE MY CHANCES OF HAVING TWINS?

  21. Kimberly says:

    What are the odds with invitro of two embryos inserted of having twins? And odds of triplets?

  22. Gary I can assure that the answer to you question is definitely false. I gave birth to twin boys my first pregnancy with no abortion or miscarriage previously.

  23. Hello,
    I was wondering if you have ever heard of anyone having two sets of monozygotic twins in one year? I am 25, caucasian and received no fertility medication to make these pregnancies occur. My oldest set was born on February 16, 2009 and the youngest were born on December 8, 2009. Have you ever come across this before? I don’t know any one my biological history, seeing as how I was adopted. My husband and I were completely astonished and believe we may be one of the only families this has happened to.
    Thanks =)

  24. Africanlegend says:

    That is interesting especially this point “Women between the ages of 35 and 39 are more likely to conceive twins.” It is almost like in the years before menopause the woman’s body kicks into a higher gear and double the prize. In general I think the this day an age due to the cost of such things having twins might be somewhat of a curse.