Wondering if you might have two or more passengers aboard your mothership? Multiple births have definitely multiplied in the past two generations. The number of twin births jumped about 75 percent from 1986 to 2009, and currently there are about 32 twins born per every 1,000 births.
What’s behind this multiple-baby boom? The surge in older moms has a lot to do with it, along with an increase in fertility treatments and the rise in obesity, say experts. Yet these are only a few of the factors behind twin births.
With these incredible stats in mind, it’s not such a stretch to wonder if you might conceive more babies than you bargained for. Here are the overall odds of having twins, along with factors that could increase your chances.
What are the chances of having twins?
Just over 3 percent of babies in the United States are now born in sets of two, three or more, with the majority — about 97 percent — of these multiple births being twins. So your chance of having twins is about 3 in 100.
What increases your chances of having twins?
A number of factors are at play when it comes to your chances of having twins, specifically fraternal twins. (Note that identical twins are rare and occur at random, so they're even more of an exciting surprise!)
Your chances of seeing double (or more) go up if:
You have twins in your family
Heredity doubles your chances of conceiving twins — but only on the mom's side. Even if your partner's family tree is loaded with dynamic duos, that won't increase your own odds of conceiving twins.
You've had twins before
Lightning can and does strike twice! If you've already given birth to a set of twins, look out — you're significantly more likely to do so again.
More About Multiples
You're 35 or older
As you age, your chance of conceiving twins increases. Researchers have found that women over 35 produce more follicle stimulating hormone (FSH) than younger women, which may cause more than one egg to drop at ovulation.
You've been pregnant before
With each pregnancy, the odds that you'll have twins go up a little, likely because with each pregnancy you’re a little bit older (which in itself ups the chances of having twins).
You're undergoing (or underwent) fertility treatments
Although fertility treatments don’t come with as high a multiples rate as they used to, having any kind of assisted reproduction (especially the kind that stimulates ovulation) ups the chances of a multiple pregnancy.
About one-third of twin births and three-fourths of triplet, quadruplet and other higher-order multiple births can be attributed to fertility treatments, according to a 2013 study in The New England Journal of Medicine, though the numbers are coming down because of improved fertility treatment protocols.
Your BMI before pregnancy was a certain range
Women with pre-pregnancy BMIs higher than 30 are significantly more likely to have fraternal twins than women with lower BMIs.
You're a Black or white expectant parent
Black and white women have a higher chance of having twins than Asian and Hispanic women. But if you're Black, you're slightly more likely to have twins than if you're white.
Are my chances of having twins higher if I have multiple factors that up my odds?
It's true! If you can check more than one of the above boxes, your chances of twins increase even more, ever so slightly.
Yes 
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