Q: What are the odds of having a multiple birth?
A: According to mathematical probabilities, the estimated odds in the United States of having spontaneous multiples (of any zygosity) are as follows:
| Twins | 1 in 83 pregnancies |
| Triplets | 1 in 6,889 pregnancies |
| Quadruplets | 1 in 571,787 pregnancies |
| Quintuplets | 1 in 47,458,321 pregnancies |
| Sextuplets | 1 in 3,939,040,643 pregnancies |
The odds of having monozygotic (all identical) multiples are as follows:
| Twins | 1 in 250 pregnancies |
| Triplets | 1 in 62,500 pregnancies |
| Quadruplets | 1 in 15,625,000 pregnancies |
| Quintuplets | 1 in 3,906,250,000 pregnancies |
According to the Centers for Disease Control’s National Vital Statistics Report Births: Final Data for 2015 (latest data available):
- 33.5 twin births occur per every 1,000 total live births
- 103.6 triplet or higher-order birth occur per every 100,000 total live births
In 2015, 137,278 live multiple birth babies were born in the United States:
- 133,155 Twins
- 3,871 Triplets
- 228 Quadruplets
- 24 Quintuplets and Above
The twin birth rate declined in 2015 to 33.5 per 1,000 total births; the 2014 twinning rate (33.9) had been an all-time high.
The triplet and higher-order multiple birth rate dropped 9% from 2014 to 2015 and is down 46% since the 1998 peak.
Factors that can increase the odds of having a multiple birth:
- Higher maternal age at conception (particularly women over age 45)
- The previous birth of fraternal twins/multiples
- A history of fraternal multiples in the female lineage
- A taller than average mother
- The use of fertility medications and assisted reproductive technology
See our Statistics & Research page for more statistics on the odds of having multiples.
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