Signs You Might Be Pregnant With Twins

When you're newly pregnant, it's normal to wonder whether you have more than one baby on board—and how early you can find out if you're having twins. Twins only account for 3% of all births in the U.S. According to the Centers for Disease Control and Prevention (CDC), there were 31.2 twins born for every 1,000 births in 2021. But there are some things that can increase your personal chances of having twins.

So how early can twins be detected? While twins can't officially be detected until you've had an ultrasound, you might experience signs that you're carrying more than one baby. We turned to the experts to learn more about twin pregnancy symptoms, how early twins can be detected, and how you might be able to tell early on that you have more than one baby on the way.

How Early Can Twins Be Detected?

In most cases, twins can be detected as early as seven weeks of pregnancy with an early pregnancy ultrasound, says Amos Grünebaum, MD, a professor of obstetrics and gynecology at the Zucker School of Medicine in Hempstead, New York, and the founder of BabyMed and Obie.

However, not all pregnant people will have access to an early ultrasound, and some health care providers may not do a pregnancy ultrasound until the second trimester.

Are There Early Signs of Twin Pregnancy?

The short answer is yes and no. Every pregnancy is different. Just like people with singleton pregnancies, people who are pregnant with twins can experience a wide range of pregnancy symptoms. That said, certain physical signs might clue you in to how many babies you're expecting, like intense morning sickness and "showing" earlier than expected.

Certain people also have a greater chance of getting pregnant with twins than others. If you're experiencing an early sign of twin pregnancy and have one or more risk factors for twins, you just might be carrying multiples.

That said, while there are some symptoms that are commonly reported among people pregnant with twins, those symptoms can't confirm or rule out a twin pregnancy. That is to say that you can experience common "twin pregnancy symptoms" with a singleton pregnancy, and it's also possible to be pregnant with twins and not experience the so-called signs.

Possible Twin Pregnancy Symptoms

While you won't know for sure that you're pregnant with twins until you have an ultrasound, there are some physical signs that are more common with twin pregnancies.

Elevated hCG levels

Higher-than-normal levels of hCG may indicate that you're pregnant with multiples. When you become pregnant, your body starts making human chorionic gonadotropin hormone (hCG). Levels of hCG start to increase after implantation and rise every 39–53 hours in the first few weeks of pregnancy. With twin pregnancies, hCG levels can be 30% to 50% higher than those where only one embryo is present.

It's important to keep in mind that the only way to measure hCG levels is through a blood test. While home pregnancy tests detect hCG in urine to confirm pregnancy, they cannot tell you how much hCG your body is producing. So even though some people swear that a darker line on a pregnancy test means more hCG (and by extension, might mean twins), that's not the case.

Only an hCG blood test, like the one done at your doctor's office, can provide a look at the levels of hCG in your body at a given point in time. And even if you do have high hCG levels in early pregnancy, it still doesn't mean that multiples are a sure thing.

"Twin pregnancies often have increased hCG levels, but so do some singleton pregnancies," explains Dr. Grünebaum. "There is a wide range of normal hCG levels both for twins and singletons, and it's impossible to be sure it's twins even when the early hCG levels are elevated."

Abnormal AFP test results

An AFP (Alpha-fetoprotein) screening is a blood test performed on pregnant people during the second trimester. Also known as maternal serum screening or multiple marker screening, it's used to identify increased risks of certain birth defects.

A twin pregnancy can produce an unusually high or "positive" result. Generally a health care provider will respond by scheduling an ultrasound for further assessment.

Exaggerated pregnancy symptoms

Since many pregnancy symptoms are caused by hormonal changes, it makes sense that people expecting twins (who often have more substantial hormonal changes than people expecting one baby) can experience more severe symptoms.

Christine Greves, MD, an OB-GYN at Winnie Palmer Hospital for Women & Babies in Orlando, Florida, explains that people who are pregnant with twins have a "higher risk" for many things, including more severe pregnancy symptoms.

People with twins may experience the same common early pregnancy symptoms as people who are pregnant with one baby, but the symptoms may feel more intense.

While more intense physical symptoms can suggest twins, severe symptoms can also occur with a singleton pregnancy.

Intense nausea and vomiting

Due to elevated levels of hCG, people carrying multiples may experience more nausea and vomiting than those carrying only one baby, explains Dr. Greves.

For instance, hyperemesis gravidarum (HG), a condition that's often compared to morning sickness, but is more severe and causes uncontrolled vomiting, is more likely with a multiple pregnancy. HG causes nausea and vomiting so severe that a person may need intravenous (IV) fluids and other assistance, Dr. Greves says.

Research has shown that twin pregnancies are associated with higher rates of severe nausea and vomiting when compared to singleton pregnancies alone. And interestingly enough, when both babies were females, the rates of nausea and vomiting were reported as even more severe. So pregnancies with twin girls may cause the most severe morning sickness of all.

A bigger "bump"

Dr. Grünebaum says the appearance of an early pregnancy bump isn't a definitive indicator of twin pregnancy because height, pre-pregnant weight, diet, body type, and number of previous pregnancies also come into play. However, many who have carried multiples say their quickly growing bellies tipped them off.

Fundal height—a measurement from the pubic bone to the top of the uterus—can be higher in twin pregnancies. However, fundal height measurements aren't typically considered accurate until after 24 weeks of pregnancy, by which point most people will already know if they are expecting twins. Additionally, fundal height measurements can be less accurate in people with obesity or a history of fibroids.

Intuition

Just as some people have a hunch they're pregnant, others might instinctively guess they're expecting twins. And while there may be no way to accurately measure a pregnant person's intuition for twins, one study found that over half of pregnant people who claimed to have an intuition about their baby's sex were accurate.

Even more impressive? The pregnant people who reported having a "very strong sense of intuition" had even higher accuracy rates, at 62% correct. So who knows? Pregnancy intuition may be a powerful thing, even with twins.

The Bottom Line

It can be fun to guess whether you're carrying multiples. But no matter how many twin pregnancy symptoms you're experiencing, you will need an ultrasound to determine how many babies you're carrying.

"You can guess as much as you want, but until you have the ultrasound examination, it's all just speculation," affirms Dr. Grünebaum. Luckily, most pregnant people don't have to wait long to know for sure. "Today, twins can usually be diagnosed as early as six to seven weeks into the pregnancy," he says.

As with anything else concerning pregnancy, if you have questions about your growing baby (or babies), be sure to reach out to a health care provider.

Additional reporting by Pamela Prindle Fierro.