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You often hear news stories about twins.
In Dallas, recently, there were stories about separating conjoined twins, an 'epidemic' of twins, triplets and quads in an elementary school, the 'natural' birth of quads (two sets of identical twins), and there was the tragic story of toddler twins who drowned in their family's pool.
All of these stories and news coverage makes it seem that having twins and higher order multiples is very common.
Is it?
There has been an increase in multiple births in recent years.
In the United States, in the year 2000, there were:
- 118,916 Twin Births
- 6,742 Triplet Births
- 506 Quadruplet Births
- 77 Quintuplets & Other Higher Order Births
That is a 74 percent increase in the number of twin births from 1980.
And since there were just over 4 million births in the United States in 2000, about 3% of babies were born as a twin or higher order multiple (triplets, quads, etc.), which although not common, does mean that multiples are more common than many people believe.
So what is your chance of having more than one baby at a time?
Basically, it is 3% or 1 in 33.
There are things that can increase your chances of having a multiple birth, including a mother being 30 or over when she conceives. For example, while there is a 3% chance of having a multiple birth at age 25-29, it increases to 4% at 30-34 years and almost 5% at 35-39 years.
Other factors that can increase your chances of having twins include having a maternal family history of multiple births (fraternal), and of course, using fertility treatments (in vitro fertilization or fertility drugs).
Your chance of having twins is also influenced by your race (multiples are more common in African Americans and least common in Hispanics and Asians), how many times you have been pregnant (the chance of having twins increases with each pregnancy), and whether or not you have had twins already.
Keep in mind that statistics for birth rates and multiple births include all births, including those that were the result of fertility treatments and those that were spontaneous or 'natural'. So if you don't have any of the factors mentioned above that can increase your chance of having multiples, your chance is going to be a little less than 3%. The chance of having 'natural' fraternal twins is only about 1.7% or 1 in 60. The chances of having twins with the use of fertility treatments can be as high as 20-25%!
Of multiple births, the rate of fraternal twins has been increasing the most, and that makes sense since the chance of having fraternal twins is influenced by an advanced maternal age and the use of fertility treatments.
The chance of having identical twins has remained steady, and is about 0.4% or 1 in 250.
Other statistics:
- chance of having conjoined twins: 1 in 50-80,000
- chance of having 'natural' triplets: 1 in 8,100 (only about 30% of triplets are 'natural')
- chance of having 'natural' quads: 1 in 729,000 (only about 6% of quads are 'natural')
- chance of having 'natural' quints: 1 in 55,000,000
How about the mom that had two sets of identical twins? The chance of having 'natural' quads that are made up of two sets of identical twins is thought to be as high as 1 in 25-36 million. It is probably lower though. An internet search found other occurrences of having 'naturally' born newborn quadruplets which were two sets of identical twins in Kansas (Tetrick quads) in 2002, in Boston in 2000 (Battles quads), and in Texas in 1995 (Collier quads). So, in the past 8 years, among about 32 million births in the US, there have been at least 4 sets of identical twin quads born, for a rate of about 1 in 8 million.
And a family in Nevada gave birth to four identical boys (Karma quads) in 1997, and two families, one in California (Khamsa/Muy quads) and another in Washington (Hulford quads) had four identical girls in 2002. The chance of 'naturally' having identical quads is thought to be about 1 in 11 to 50-600 million (depending on who you ask).
Dr. Iannelli is the proud father of identical twin boys and a somewhat helpful stepson who is still wondering why we had to bring home two babies at the same time.
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