Potential Signs and Symptoms of a Twin or Multiple Pregnancy

Only an ultrasound can confirm twins, but there may be early clues

Some mothers who are pregnant with twins say they suspected they were carrying more than one baby from the start. Yet other mothers are surprised when they find out that they are having twins. 

The truth is that while there are several signs and symptoms of a twin pregnancy, there is also tremendous overlap with the signs and symptoms of singleton pregnancies.

It is impossible to definitively know whether you are carrying twins (or multiple babies) by simply gauging how you feel or going off of what a home pregnancy test shows. In fact, only an ultrasound can confirm a twin or multiple pregnancy.

That said, it can be exciting to wonder whether certain symptoms or signs are subtle clues that you or a loved one may be carrying more than one baby. Let's take a closer look at these potential hints at multiple babies. 

Elevated HcG Levels in Urine or Blood (Pregnancy Tests)

Pregnant woman holding baby booties
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You cannot conclusively distinguish a single pregnancy from twins on a urine pregnancy test. That said, you may have a very early positive pregnancy test if you are carrying twins. If you are using a regular pregnancy test (not the super-sensitive variety) and get an immediate positive (especially a very dark positive indicator) a few days before your period is due, there may be an increased chance that you are carrying twins.

But, remember, at-home urine pregnancy tests are not reliable when it comes to predicting the amount of hCG; they simply measure whether or not a minimum amount of hCG is present. In other words, chances are that an early positive or dark test result simply means you have had less water to drink at the time you took the test.

A blood pregnancy test (hCG level), however, may give you a better, but still not conclusive hint that you are carrying twins. ​​HCG is a hormone detectable in pregnant women's blood or urine about 10 days post-conception and usually doubles every two to three days, peaking at about eight to 11 weeks into the pregnancy.​

Regardless, elevated hCG levels in early pregnancy isn't a proper way to detect twins. One reason is that these levels are not frequently checked unless you are going through fertility treatment.

Another issue is that the normal range of hCG can vary widely between different women. For example, levels between 18 mIU/ ml and 7,340 mIU/ml are considered "normal" at five weeks gestation. Finally, In addition to multiples, there are other causes of an elevated hCG level, like a molar pregnancy.

And, all of this assumes that your estimated due date is very accurate, which is also uncommon. It's a real possibility that you may have miscalculated your missed period or when you ovulated.

Doppler Heartbeat Count

Listening to heartbeats with doppler fetal monitor
Listening for two heartbeats. Oleksiy Maksymenko/Getty Images

Using harmless sound waves, a Doppler system amplifies fetal heart sounds, usually distinguishable late in the first trimester. An experienced physician or midwife may be able to detect more than one heartbeat, indicating a multiple pregnancy.

Listening to a baby's heartbeat early on in pregnancy, however, can easily be misleading. What appears to be a second heartbeat may actually be the same baby's heartbeat heard from another angle (or as an echo).

A mother's heartbeat is not usually mistaken for a baby as it is usually only half the rate of the baby's heart rate. Still, the mother's heartbeat may create background noise which can make it hard to distinguish the heartbeats of two or more babies.

More Morning Sickness

Morning sickness
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There is a saying about twins: "Twice as sick, three times as tired, and four times the weight gain." But this is, in many ways, an old wives' tale.

Statistically, moms of multiples may experience more morning sickness, but using the degree of morning sickness as an estimate that you are carrying twins isn't necessarily very helpful. 

Overall, about half of women experience some amount of nausea and vomiting with single pregnancies, and up to 1 percent experience hyperemesis gravidarum, a form of severe morning sickness. At the same time, some moms of twins and triplets say they have no morning sickness.

Also, with a first baby, a woman doesn't have a reference point to compare her degree of nausea. But with second babies and on, around 15 percent of women reported more morning sickness with multiples than with previous single pregnancies.

Finally, another potential sign is that in women carrying multiples, nausea may begin quite early, even before a pregnancy test turns positive. Again, though, this is not a fact, simply an observation. 

Weight Gain

Pregnant woman standing on scales
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While mothers of twins only gain about 10 pounds more than singleton mothers, the amount of weight a woman gains often depends more on her height, body type, and how much she weighed pre-pregnancy than the number of babies in her uterus.

In addition, much of the increase in weight gain occurs later on in pregnancy, often after an ultrasound has already confirmed or excluded a diagnosis of twins or other multiples.

Finally, your diet could be a reason why you are gaining too much weight. You may be taking in more calories than you need. If you are concerned about your weight during pregnancy, please talk to your doctor about seeing a prenatal nutritionist. 

Abnormal AFP Test Results

Midwife taking blood sample from arm of pregnant woman Obstetric examination. Midwife taking a blood sample from the arm of a pregnant woman. Regular check- ups are necessary during pregnancy so that the development of the baby and the health of the mother can be monitored. Blood can be tested to provide information on the mother's nutrition, for example blood glucose levels, and levels of hormones and antibodies.
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AFP (Alpha-fetoprotein) screening is a blood test performed on pregnant mothers 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, your doctor will respond by scheduling an ultrasound for further assessment. 

Measuring Large for Gestational Age

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Throughout your pregnancy, your doctor or midwife will measure the height of your uterine fundus (measuring from the top of the pubic bone to the top of the uterus) as a way of estimating gestational age as well as the growth of the baby.

A twin or multiple pregnancy may cause the mother's uterus to expand beyond the range of a single pregnancy. However, other factors may also increase the measurements. This measurement is more difficult earlier in pregnancy than later on, when an ultrasound may have already detected the presence of twins.

Of course, there are other reasons why you may be measuring large or "showing larger or sooner" than you expected. If you have been pregnant in the past, you will likely show sooner. In addition, you may be measuring large if your date of conception is inaccurate or if your baby is simply bigger.

 

Fetal Movement

Pregnant woman unable to sleep
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Feeling a baby (or babies) move inside the womb is one of the most thrilling aspects of pregnancy.

"Quickening," or the time at which you first feel your baby, can occur anytime between 18 and 25 weeks but is usually detected earlier in subsequent pregnancies, perhaps as early as 16 weeks. When women feel movement in early pregnancy is often inconsistent and can be deceiving.

Although many moms of multiples do experience more frequent or earlier fetal movement, there is some disagreement among medical professionals on the subject. For some women, recognizable feelings of movement occur earlier in subsequent pregnancies, whether there is one baby or more. In addition, be aware that what may seem like fetal movement in early pregnancy may actually be gas or an upset stomach.

Severe Fatigue

Pregnant Japanese woman napping on sofa
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Extreme fatigue is the most commonly reported complaint during pregnancy with multiples. Sleepiness, lethargy, and exhaustion during the first trimester can be enhanced because the body is working overtime to nurture more than one baby.

In some cases, the fatigue can be attributed to other factors (work, stress, poor nutrition, having other children), but it can also indicate multiples.

The degree of fatigue can, however, be difficult to assess, at least as it relates to twins. We know that fatigue is almost inevitable in pregnancy, even with singletons.

Remember, first-time moms don't have a reference point for a "normal" degree of fatigue. Second-time (and more) mothers may note increased fatigue, but attribute this to the demands of having to care for young children while pregnant. Still, mothers who have had previous pregnancies may note that they are much more tired.

Again, fatigue is a rather subjective symptom and has many potential culprits. 

Gut Feelings and Hunches

Pregnant woman lying in bed
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While the other items in this list refer to some kind of visible evidence—exaggerated symptoms, abnormal test results, increased morning sickness and more—we can't disregard the power of a mother's intuition. Whether mothers-to-be have dreams of twins or a hunch they can't explain, those who have cared for pregnant women quickly learn to listen. Some of the best "hints" indicating a multiple pregnancy aren't easily explained in medical textbooks.

If you simply have a "gut feeling" that you may be carrying multiples, listen to your body and talk to your doctor about these feelings.

Ultrasound Confirmation

Ultrasound scan
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Seeing is believing. The only way to indisputably confirm a twin or multiple pregnancy is to see it via ultrasound. An ultrasound image can indicate without a doubt if there is more than one fetus. Ultimately, no matter what other signs or symptoms you have, the only way you'll know is to have an ultrasound.

If you have suspicions that there may be more than one baby, discuss your concerns with your doctor. It's very unlikely that an ultrasound view would miss an additional baby, especially in the second or third trimester. However, there have been cases of hidden twins. In particular, a "hidden" twin is more likely on an early ultrasound when the babies are identical (monochorionic) twins.

Sometimes extreme higher order multiple pregnancies, such as quintuplets or sextuplets, are also too difficult to count accurately on an early ultrasound.

A Word From Verywell

In the end, if you've learned you have twins, it's common to experience a range of emotions from excitement to panic. Be sure to not only discuss your symptoms with your doctor, but also your anxieties, questions, and the risks involved with having a twin (or multiple) pregnancy.  

Sources:

American Pregnancy Association. (2016). Signs & Symptoms of Multiple Pregnancy. 

Chasen, S., and F. Chervenak. (2017).  Twin Pregnancy: Prenatal Issues. UpToDate. Updated 05/10/17.

Khalil A. et al. ISUOG Practice Guidelines: Role of Ultrasound in Twin Pregnancy. Ultrasound in Obstetrics and Gynecology. 2016. 47(2):247-63.

Mackie, F., Morris, R., and M. Kilby. The Prediction, Diagnosis and Management of Complications in Monochorionic Twin Pregnancies: The OMMIT (Optimal Management of Monochorionic Twins) Study. BMC Pregnancy and Childbirth. 2017. 17(1):153.

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