Physical Symptoms When Carrying Twins 

While certain physical symptoms may lean toward double trouble, the only sure confirmation of twins is a medical ultrasound. 

For most women, the answer will come during the first trimester ultrasound. Set around weeks 11 to 14, this scan can detect the amniotic sacs, placentas, or even body parts of twins inside the womb at 99.8% accuracy. 

Until then, you can keep an eye out for the following twin pregnancy symptoms, which strongly correlate to multiple children in the womb.

#1 Your Belly is Growing Large….Very Large 

It makes sense—the more kids you carry, the larger your belly has to grow! 

If you are carrying twins, your bump will likely be pretty large for its gestational age (a.k.a., how far along you are in your pregnancy). Medical professionals use fundal height to mark gestational age, measuring the growing distance between the top of your pubic bone and the top of your uterus (a.k.a., your fundus). 

Since twins need more belly room, they usually create a higher-than-average fundal height. 

But don’t break out the measuring tape just yet. Your healthcare provider typically determines fundal height during a physical exam where they’ll measure the space between the top of your public bone and the top of your uterus. At 12 weeks, the fundus is usually only as high as the pubic bone, making accurate at-home measurements difficult to take before this point. 

However, if you’re carrying twins, you don’t really need an exact measurement—if you notice a slight bump well before 12 weeks, it could be because you have an extra womb tenant.

#2 You’re Gaining Weight Fast 

It’s normal to gain weight during pregnancy—it’s part of how your body supports your little one. But if you’re carrying twins, this weight might come on faster and heavier than usual.

For single-child pregnancies, medical professionals say that healthy pregnancy weight gain falls between 25 to 35 pounds. This weight gain usually starts slow, then picks up speed, filling in over the trimesters like so:

• First trimester (weeks 1 to 13) – add 2 to 4 pounds
• Second trimester (weeks 14 to 27) – add 12 to 20 pounds
• Third trimester (weeks 28 to 36) – add 12 to 20 pounds

Two tiny mouths to feed will increase the amount of weight gain you’ll experience. According to medical experts, most twin pregnancies should gain between 35 to 45 pounds for healthy growth. Take a look at how this weight fills in across each trimester:

• First trimester (weeks 1 to 13) – add 4 to 6 pounds
• Second trimester (weeks 14 to 27) – add 16 to 20 pounds
• Third trimester (weeks 28 to 36) – add 16 to 20 pounds

#3 You Feel Bumps and Thumps Pretty Early 

Kicks, bumps, shifts, thumps—they’re all exciting signs that your baby (or babies) are living it up down there. 

Often referred to as “quickening,” a baby’s first movements inside the womb are a thrilling and joyous occasion. Most moms feel these little flutters around 18 to 22 weeks into pregnancy. 

While not research-backed yet, frequent and early fetal movement (i.e. any time before 18 weeks) could mean that you have two little dancers grooving inside of you!

#4 You’re Feeling Sick 

Are you getting nauseous from certain food smells? Like…really nauseous? This pregnancy symptom could indicate a double dose of baby in your womb. 

Morning sickness is a common first–trimester symptom. In fact, about 70% of pregnant women experience it. This is because human chorionic gonadotropin hormone (hCG) spikes after conception, warning your body that a baby is coming—and often triggering morning sickness. Common symptoms of morning sickness include:

• Nausea
• Vomiting
• Loss of appetite
• Fatigue

Where do twins fit into all of this? Research shows that carrying more than one baby possibly boosts hCG levels. As a result, you experience boosted ick’s and ew’s during your first few months of pregnancy. 

#5 You’re Tired (Like, Really Tired) 

Carrying one baby 24/7 is hard enough on your body. Carrying two? That’s a double-time job. 

If you’re feeling crazy levels of fatigue while pregnant, there’s a chance you might be conceiving twins. Elevated hormones from carrying two fetuses can leave you feeling doubly exhausted, so remember to take it easy during this time and allow yourself plenty of rest. 

A Twin Timeline 

From their tiny beginnings to their big entrance, twin fetuses have quite an extraordinary journey. Let’s dive into the typical fetal timeline and what you might experience along the way if you’re pregnant with twins.

Identical vs. Fraternal 

This is where the magic begins. Either right before or after conception, your body makes a clear distinction for twins—identical vs. fraternal. 

Both biological “errors” (albeit very adorable errors), identical and fraternal twins are the result of completely different processes. Over the first few weeks, see how these types of twins come to be during pregnancy:

• Identical twins – In days following conception, identical (or monozygotic) twins form from one fertilized egg splitting into two. This is why identical twins share 100% of their DNA, creating lookalike appearances. Identical twins account for just 0.45% of total births in the US.
• Fraternal twins – Unlike identical twins, fraternal (or dizygotic) twins come from two separate eggs and sperm cells. This is the result of hyperovulation—when an ovary releases two eggs in one ovulation cycle. When both eggs are fertilized, you get twins who share 50% of their DNA (just like normal siblings). The chances of having fraternal twins are slightly higher than identical twins, with fraternal twins accounting for 3.11% of total births in the US. 

First Trimester: Weeks 1 to 13 

Even early in your twin pregnancy, you’ll start to notice pregnancy symptoms (like that fun super-powered morning sickness we talked about). 

While you’re sipping on some ginger tea, you can think about how your little ones are growing during this exciting time:

• Week 1 – After fertilization in the fallopian tubes, your egg(s) are considered single-cell zygotes. They then travel down into the uterus, rapidly dividing into more cells to become multi-cell blastocysts. At this point, if it was a single egg, the single blastocyst will split into two, to form identical twins. Fraternal twins will already be separate blastocysts.
• Week 2 – Next up, your two blastocysts will secure themselves to your uterine wall in a process known as implantation. When this happens, you might experience implantation bleeding, which looks like light spotting (but is not a period). With twin pregnancies, implantation bleeding may be more common since two blastocysts disturb the uterine lining. 
• Weeks 2 to 4 – After implantation, the placenta (the organ that passes nutrients) and the amniotic sac (a protective membrane) will begin to form around the twins. For fraternal twins, each baby will get his or her own placenta and sac. For identical twins, it depends on when the single fertilized egg splits into two. About 30% will have their own placenta and sac (like fraternal twins), about 70% will share the same placenta but have their own sac, and about 1% will share the same placenta and amniotic sac. 
• Weeks 5 to 8 – All major organs begin to form for your twins, alongside tiny beginnings of arms and legs. Meanwhile, helloooo fatigue and sore breasts. 
• Weeks 9 to 13 – Small features like toes, fingers, and noses start to fill in here. In fact, by week 13, you can detect two little faces. You also might begin to experience other first trimester symptoms, like increased urination and food cravings.

Second Trimester: Weeks 14 to 27 

By the second trimester, your twins are starting to pick up speed. You’ll notice increased weight gain as they continue to grow over this timeline:

• Weeks 14 to 17 – Most moms feel their quickening (or first baby movements) around week 18, but twins may start moving earlier. And in other exciting news? You can also say goodbye to many rocky first trimester symptoms—the second trimester is usually a smoother journey.
• Weeks 18 to 22 – Your babies will start to act like…well, babies. Get ready for more movements as your twins kick around trying to get comfortable and start to suck their thumbs.
• Weeks 23 to 27 – Now’s the time to start practicing your lullabies. Many babies show responsiveness to noise from inside the womb at this point. Lungs and fingerprints also develop around this time. 

Third Trimester: Weeks 28 to 36 

Now, it all comes together in two-part harmony. Here are your twins’ final growth spurts:

• Weeks 28 to 32 – Your twins are continuing to grow into their full selves, developing functioning eyes and even body hair. However, the extra weight may start to feel uncomfortable for mom. Increased fatigue, hemorrhoids, and joint pain are common at this point.
• Weeks 33 to 36 – Single babies average 40 weeks for gestation, but twin pregnancies usually take just 36 weeks, so it’s important to be prepared for any early arrivals (as if you haven’t been preparing since the moment you received the miraculous news).

Double Down on Your Pregnancy Knowledge with SneakPeek 

Twins are the ultimate surprise, and by listening to your body’s signals, you may be able to get a heads up (or dare we say, a Sneak Peak) about the two buns in your oven. 

Whether you’re expecting one baby or two twin babies, we can provide a glimpse into another exciting development—the gender of your baby (or babies) to-be.

The SneakPeek At-Home Early Gender Prediction Test is the only at-home fetal sex test on the market that can determine your baby’s gender with over 99% clinically proven accuracy¹ as early as 6 weeks into your pregnancy. That’s months before your 18 to 20 week anatomy ultrasound! It’s even recommended and rated #1 by OBGYNs. 

If pregnant with twins, our Gender Blood Test will look for male DNA in mom’s blood to determine if at least one of your babies is a boy. If no male DNA is detected, you can expect twin girls coming your way. If male DNA is detected, you either have a boy and a girl, or two boys. SneakPeek cannot detect if both babies are boys based on the amount of male DNA, only if you’re carrying a boy at all.

Most importantly, we privacy protect your data and results, so you can trust your information is safe with us. Join the over 1 million happy moms who chose SneakPeek Test and let us be your guide along your pregnancy journey.