What Are the Chances of Having Twins With Clomid?

Odds for Twins, Identical vs Fraternal, and Other Twin Boosting Traits

Mother holding twin baby boys
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Clomid twins are less common than you think. Media reports of women having high-order multiples—from quadruplets to quintuplets!—gives the impression that fertility drugs frequently lead to multiple pregnancies.

First, it's important to know that high-order multiples are more likely with injectable fertility drugs. It's extremely unlikely you'll have triplets or quadruplets on Clomid. Second, even your odds for twins on Clomid aren't that high.

Here are the facts.

What Are the Odds?

Clomid causes twin pregnancies between 5 and 8 percent of the time. That's less than 1 in 10 pregnancies. Your odds of conceive triplets (or more) on Clomid is less than 1 percent. (That's less than 1 in 100 pregnancies.)

During clinical trials for Clomid, about 7 percent of pregnancies led to twins, about 0.5 percent of pregnancies led to triplets and 0.3 percent to quadruplets.

How does Clomid increase your chances of having twins? The female reproductive system works via a complex feedback system. When certain hormones rise, others lower. Your ovaries contain hundreds of thousands of follicles. Inside these follicles are immature egg cells.

Each month, several follicles begin a process of development. However, (usually) only one of these follicles fully develops and releases an egg. This is because once a follicle becomes strong enough on its own, the follicle releases hormones into the blood stream that signal your body to decrease the egg-stimulating hormones.

Clomid works by tricking your body into thinking there's no dominate egg developing in your ovaries. In response, your body increases egg-stimulating hormones. This in turn causes the follicles in your ovaries to continue to mature, and this increases the risk of more than one egg developing to maturity and ovulating.

What Other Factors May Increase My Odds for Twins?

While it's impossible to know who will get pregnant with twins while taking Clomid and who won't, there are some factors that may hint to an increased chance of getting pregnant with twins.

Using a higher dosage than necessary may increase the risk of having twins. Ironically, using a higher dosage of Clomid than necessary may also decrease the chances of pregnancy occurring at all because higher doses of Clomid can create thick cervical mucus.

Women taking Clomid who do not have trouble ovulating or getting pregnant, as well as women younger than 25, may have an increased risk of getting pregnant with twins while taking Clomid.

Fertility drugs aren't the only cause for multiple pregnancies. Even without Clomid's help, your odds for getting pregnant with more than one baby increase depending on your age, height, weight, and family history.

Will They Be Identical Twins?

Most twins conceived with Clomid will not be identical. During the clinical trials of the twin pregnancies, 1 in 5 were identical twins, while 80 percent of the twin pregnancies were fraternal twins (not identical).

Why aren't they identical? Clomid increases your odds of conceiving twins because your ovaries may ovulate more than one egg.

Identical twins come from one egg, not two.

"I Don't Have Infertility, But I Want to Get Pregnant With Twins. Should I Take Clomid?"

Some women ask their doctors to give them Clomid, not because they are having trouble getting pregnant, but just because they want to get pregnant with twins. Some women will even lie to their doctors about trying to conceive (saying they have been trying for a long time when they haven't), in hopes they can get a prescription.

Twins are adorable, for sure, but a twin pregnancy is not risk free. Multiple pregnancies come with possible health consequences for both the mother and child.

You should think twice before purposely trying to get pregnant with twins.

How Will I Know if I Got Pregnant with Twins While Taking Clomid?

You won't know if you conceived twins until you can have an ultrasound. While some say that pregnancy symptoms are stronger with twins, this isn't necessarily true. You can have intense "pregnancy symptoms" and have just one healthy singleton. For that matter, you can feel pregnant and not actually be pregnant.

Getting an early positive result on a pregnancy test or having high levels of hCG on a blood test are not reliable signs of a twin pregnancy either.

Depending on your health history, your doctor may order an ultrasound at the six-week mark. (This would be two weeks after your period was late.) This may be too early to detect twins. Sometimes, the ultrasound tech can only see one yolk sac. However, by week 8, a twin pregnancy should be visible.

Sources:

Clomid Drug Information Sheet. Sanofi-Aventis.

Multiple Pregnancy and Birth: Twins, Triplets, and High Order Multiples. American Society of Reproductive Medicine.

Medications for Inducing Ovulation. American Society of Reproductive Medicine.

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