What Are My Odds and Chances of Having Twins?

Statistics about twins, triplets, and multiple births

Couple on bed with twin babies.
Getty Images / Jade Brookbank

What are the chances of having twins? Odds are, if you're already a parent of multiples, you may find yourself marveling at your unusual family dynamics and think "Why did this happen to me? How did I get so lucky?" (or unlucky, depending on the moment!)

If you're not yet a parent of multiples, you might wonder what it takes to become one. Are you a candidate for twins, triplets, or more?

The odds of having multiples are influenced by many factors, both personal and at the population level. Twinning rates have changed throughout the years because of these changing influences.

It can be interesting to analyze the statistics and contemplate your personal odds for winning the multiples lottery. However, keep in mind that these statistics (the odds or chances of having twins or multiples) are based on populations, not individuals.

It is not possible to quantify a specific number for a person—for example, saying that their particular chance of having twins is 1 in 100. Rather, curious parents can consider the statistics for entire populations in relation to the factors that increase or decrease the chances of having twins.

General Statistics About Twins and Multiples

Within the general population in the 21st century, the chances of having twins are about 3 in 100 (about 3%). That said, your chances are better than ever (or at least, better than previous generations).

Researchers have recorded an increase of nearly 60% since the early 1980s. The most recent statistics, published as part of a 2019 study by the National Center for Health Statistics, show that twins represent 32.1 of every 1,000 births.

You'll increase your odds of having twins/multiples if:

  • You take fertility drugs or other fertility treatments. Research appears to show that fertility enhancements have contributed to increased multiple birth rates. However, the odds of having multiples can vary between treatment types. For example, estimates show a 11.7% chance of twin births in couples using the drug Clomid. A study on assisted reproductive technology (ART) found that 25.6% of the resulting live births involved twins (13,123 out of 51,262 live births.).
  • Your sister, mother, or your mother's mother had fraternal twins. Women who have lots of multiples in their family might carry several genes for hyperovulation (meaning that they release more than one egg during an ovulation cycle). Hyperovulation increases the ability to conceive fraternal twins. The genes affecting twinning are carried through maternal line, so if your father is a twin, that won't necessarily affect your chances of having twins.
  • You live in Michigan or Connecticut. A 2018 study found that these two states had the highest twin birth rates in the U.S. — 35.9 and 36.4 per 1,000 births, respectively.
  • You live in Africa or North America. A study looked at twinning rates across the globe between 2010 and 2015. Africa was the continental region with the highest rate with 17.1 twin deliveries per 1,000 births. North America had the second highest rate of any region with 16.9 twin deliveries per 1,000.
  • You (the mother) are over age 45. Research has shown that the chance of having twins increases with age. In a study of pregnant women over the age of 45, 16% had multiple pregnancies, with twins being the most common outcome.
  • You (the mother) have obesity or are tall. A study published in 2005 reported a significant increase in fraternal twin births to mothers who had a BMI of 30 or higher, or who were in the top 25th percentile for height.

You'll decrease your odds of having twins/multiples if:

  • You (the mother) are Hispanic. A study by the National Center for Health Statistics found that women of Hispanic origin were substantially less likely to have twins than non-Hispanic White or Black mothers.
  • You live in Asia or South America. Between 2010 and 2015, the global average twinning rate was 12 twin deliveries per 1,000 births. The continental region with the lowest rate was Asia, having a rate of 9.2 per 1,000. South America had a similar rate of 9.3 per 1,000.
  • You're relying on the chances of identical multiples. The rate for identical (monozygotic) multiples is random and universal. This means the chances are the same in all populations regardless of race, heredity, or other factors. The rate of having identical twins has remained constant over time and is about 3 to 4 per 1,000 births.

Odds of Triplets/Quadruplets/Higher Order Multiples

Researchers have noted a substantial increase in the rate of triplet and higher-order multiple births over the last 40 years. In 2019, the birth rate for this population was 87.7 per 100,000 births (or 0.877 per 1,000 births, if you want to compare it to twinning rates). It is estimated that around 77% of triplets and higher order multiples are the result of fertility-enhancing treatments.

The odds of conceiving "spontaneous" triplets (i.e., without the aid of fertility enhancements) are about 1 in 8,100. The odds of having spontaneous quadruplets are even higher—predicted to be 1 in 729,000.

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