Twins
Resources for twins and parents of twins
What are the odds or chances of having twins?

The chances of having twins in 2003 was 3.1% or 1 in 32. The odds of having twins naturally was 2.11% or 1 in 47. The probability of having twins overall has risen drastically since 1980 when it was 1.89% or 1 in 53. So the chances of conceiving twins in 2003 rose 67% from 1980. This drastic increase in twin birth rate has been widely attributed to women waiting longer to conceive, the use of fertility drugs, and the use of in vitro fertilization(IVF).

A study done in the year 2000 estimated that approximately 67% of all twins were conceived without the use of IVF or fertility drugs such as Clomid.

The chance of having identical twins is approximately 1 in 250 or 0.4%. Historical twin statistics show that identical twins made up roughly 33% of all twin births. Currently only about 12% of all twin births are identical twins. The use of fertility drugs or in vitro fertilization does not increase the probability of having identical twins.

So what are some of the ways to increase the chances of having twins? As mentioned above, the use of fertility drugs can increase the odds of having twins to as high as 20% or 1 in 5. In vitro fertilization has a 25% chance of having twins or 1 in 4. In 1980, the majority(65%) of twins were conceived from a mother ages 20-29.

YearBirthsTwinsTriplets or More
20034,089,950128,6657,663
20024,021,726125,1347,401
19973,880,894104,1376,737
19963,891,494100,7505,939
19953,899,58996,7364,973
19943,952,76797,0644,594
19934,000,24096,4454,168
19924,065,01495,3723,883
19914,110,90794,7793,346
19904,158,21293,8653,028
19894,040,95890,1182,798
19883,909,51085,3152,385
19873,809,39481,7782,139
19863,756,54779,4851,814
19853,760,56177,1021,925
19843,669,14172,9491,653
19833,638,93372,2871,575
19823,680,53771,6311,484
19813,629,23870,0491,385
19803,612,25868,3391,337

Source: US Census Bureau

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