The physical manifestation of pregnancy is belly size and growth. While your belly usually expands due to the growing baby, there are a few other factors at play.
Many pregnant women are curious about when and how their belly will grow in size. Let’s take a look at how your baby bump grows in each trimester and how your baby grows inside your womb.
Belly size in pregnancy: When does the baby bump start to show?
As eager as you are to show off your baby bump, it can be difficult to predict when it will pop. First-time mothers typically begin to show between 16 and 20 weeks, though some may not notice a bump until later in the second trimester.
For women who have previously been pregnant, the timeline is usually shorter; in this case, you may notice signs of a bump as early as the first trimester. Again, every mom-to-be and the baby bump is unique, so it’s normal to start showing a little earlier or later.
Tummy size in pregnancy
There is a method on how to compute the range of your tummy size in pregnancy. You need to start from the number of weeks that you are pregnant. Then, add two to that number and subtract two also to that number. For example, if you are in your 20 weeks of pregnancy, your tummy size may range from 18 to 22 centimeters.
What factors affect belly size during pregnancy?
Image from iStock.
Each pregnancy is unique. When and how big your belly bump will depend on a few factors, including:
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Total number of pregnancies
Between 12 and 16 weeks, first-time mothers can expect to see a noticeable belly expansion. Bloating and constipation are common pregnancy symptoms, and they can cause your waistband to feel tight even before you reach 12 weeks. People who have previously been pregnant tend to show earlier because their abdominal wall has already stretched.
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The number of fetuses
If you’re expecting multiples, your bump will most likely be visible earlier.
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Body structure
A belly bump may be visible earlier in people with lower body weight than in people who are overweight. It may not be obvious until the 20th week of pregnancy in some cases.
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Body’s framework
If you’re smaller or more petite, your growing belly may be more visible sooner.
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Abdominal muscles
If your abs were taut prior to becoming pregnant, your core may hold its shape for a longer period of time before your belly begins to pop.
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Previous pregnancy
Most women’s ab muscles relax after having their first child. This could imply that they will appear earlier in subsequent pregnancies.
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Weight gained during pregnancy
If you’re gaining weight in general, your belly may begin to expand as well. The amount of weight you should gain during pregnancy is determined by your starting weight. Consult your doctor if you are concerned that you are not on track.
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Age
Being in your twenties generally means you have stronger core muscles, so your bump may take longer to appear.
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Fetus’ position
The position of a fetus may also influence how big or small an expectant mother appears. The bump is caused by the baby’s growth above the pelvic bone. Because your uterus is still under your pelvic bone in the early stages of pregnancy, the expansion isn’t as noticeable.
Pregnancy tummy size and growth chart
Everyone’s timeline is different, and your belly will most likely not look exactly the same as another pregnant woman, even if you have the same due date! However, as your pregnancy progresses and your baby grows larger, you can expect your bump to become rounder and more pronounced.
The pregnancy tummy or belly charts depict the changes in your belly that you may notice as the baby grows. It is an approximate chart, and measurements and changes may differ from one woman to the next. Here’s how that might look:
Usually, in this period, the proof that you are pregnant is not yet visible in terms of your pregnancy belly size. Unless you use a pregnancy test kit, you will not yet know that you are pregnant.
Belly size in pregnancy: First Trimester (Weeks 1 to 12)
During your first trimester, you will most likely not feel like yourself. However, your stomach will most likely look the same as it did before you received the positive test result. Your baby is only the size of a vanilla seed at 3 weeks pregnant!
But she won’t be that small for long. By the end of your first trimester, at week 13, your baby will be the size of a lemon and weigh about 3 ounces. Many women notice that their bellies are changing at this point, but they haven’t yet reached bump territory. Instead, your tummy may protrude a little more than usual, as if you ate a particularly large meal.
Remember that every woman is different, and if you look pregnant by the end of the first trimester — or still have no sign of a bump — that’s also normal.
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First Trimester (Week 1-12)
|
| Month |
Weeks |
Belly size |
Fetal Development |
| First month |
1-4 |
There is no change in belly size. |
The fetus is about 1/4 inches long. |
| Second month |
5-8 |
A firm stomach with little variation in belly size |
The fetus is about one inch long. |
| Third month |
9-12 |
A small bump appears at the bottom. |
The fetus is approximately four inches long. |
By the end of this trimester, your clothes should feel a little tighter. Because your uterus has grown to the size of a large grapefruit, your clothes become too small during this time.
But there’s no rush to buy maternity clothes unless you’re too excited to wait, which we completely understand!
Belly Size and Growth in Pregnancy: Second Trimester (Weeks 12 to 27)
Things are probably starting to pick up in terms of size right now. (So get your maternity clothes ready!) Even if it’s not yet obvious, by week 14, you might be able to feel the top of your uterus if you gently press between the top of your pelvic bone and lower abdomen — a sign of the impending bump.
And, by week 20, your swollen uterus will have pushed your abdomen forward, most likely giving you a little bump. If you have an innie belly button, you may notice it begins to protrude at the same time as the rest of your tummy. (After you give birth, it should return to its original shape, albeit a little stretchier.)
All of the changes in the appearance and shape of your belly are, of course, signs that your baby is growing rapidly. She’s about the size of a navel orange at week 14, but by the end of the second trimester, at week 27, she’s the size of a cabbage and weighs about 2 pounds.
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Second Trimester (Week 13-24)
|
| Month |
Weeks |
Belly size |
Fetal Development |
| Fourth month |
13-16 |
The belly expands and becomes visible. |
The fetus is approximately six inches long. |
| Fifth month |
17-20 |
The belly button is prominent; it is visible, and its shape varies. Some are high, some are low, and some have a bulge in the middle. |
The baby may reach a height of ten inches. |
| Sixth month |
21-24 |
The belly doubles in size and resembles a basketball. |
The baby grows to be about 12 inches tall. |
During your second trimester, you can expect to feel your baby move and have pain on the lower sides of your abdomen (also known as round ligament pain).
Growing pains are the equivalent of round ligament pain. It occurs as a result of the muscles and ligaments that support your growing uterus stretching.
The belly itch is another symptom to look for during the second trimester. Itchy bellies are common in pregnant women.
This is because as your belly grows, your skin stretches rapidly, depriving your skin of moisture. But it doesn’t have to be that way.
Linea nigra and stretch marks on pregnant women. | Image from iStock.
The linea nigra is another intriguing second-trimester development. This is a dark vertical line that runs down the center of your stomach.
While it may surprise you (especially if this is your first pregnancy), you’ll be relieved to know that it’s caused by your changing hormones and is completely harmless.
This unique belly line will also be around for a while. However, it is normal for it to fade a few months after giving birth.
Belly size and growth in pregnancy: Third Trimester (Weeks 28 to 40)
During this final stretch, your baby gains a lot of weight as your belly grows from big to, well, much bigger! Your tummy will have likely expanded to the point where you can no longer see your legs or feet when standing up early in your third trimester.
Between 34 and 35 weeks, your baby will have grown to the size of a 5-pound bag of flour, while your belly continues to expand. Your cutie’s quarters are definitely getting cramped, and it may appear that you can’t possibly get any bigger at this point. But there’s a good chance you will! Between 35 and 40 weeks, most babies gain anywhere from one to several pounds.
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|
| Month |
Weeks |
Belly size |
Fetal Development |
| Seventh month |
25-28 |
The baby’s growth slows, and the size of the belly may remain constant or increase. |
The baby is now 14 inches tall. |
| Eight month |
29-32 |
The belly size is the same, but it appears larger. |
The baby would grow to be 18 inches tall. |
| Ninth month |
33-36 |
The stomach appears curvier and larger. |
The baby would be between 18 and 20 inches tall. |
During the last few weeks of your pregnancy, you will most likely go through a lot of changes. Because there isn’t much space in your belly anymore, your baby is pressing against your lungs and bladder.
Expect some shortness of breath and more bathroom visits during the third trimester due to the position of your uterus (if that’s even possible!).
Image source: iStock
Because of the weight gain and extra fluid in their bodies, many women experience mild swelling of their ankles and feet. You can reduce some of the swellings by doing the following:
- Avoid standing for an extended period of time.
- Remember to stretch frequently if you are sitting for an extended period of time.
- Raise your feet while sitting.
- Drink plenty of water
While swollen feet are fairly common, it is also important to pay attention to your body.
If the swelling does not go down after following the above tips (or if you notice extreme swelling in your fingers and face as well), you should contact your doctor as this could be a sign of a serious condition known as preeclampsia.
Types of pregnancy belly shape
By the time moms enter their third trimester of pregnancy, they might know if they are carrying high or carrying low. Some folk narratives suggest that you may know your baby’s gender on how you carry your baby.
These tales are not scientific enough to prove that you can determine baby’s gender by the types of pregnancy belly shape. The way moms carry their babies has something to do with their physiological makeup and the strength and composition of their abdominal muscles.
The following are the ways in which pregnant women carry their babies that gives different pregnancy belly shape:
Carrying high
Typically, younger pregnant women are possible to carry higher. This means that the largest part of the abdomen or the part that extends the furthest is high on a woman’s abdomen.
Shorter moms (in height) may also carry higher because there is less space between the pubic bone and the top of the abdomen.
Carrying low
This pregnancy belly shape means that the largest part of your abdomen is drawing lower and closer to the pelvis. This shape is common with pregnant moms having multiples, second or third pregnancies, or weaker abdominal muscles.
Carrying wide
If your pregnancy belly shape is wide, it is possible that your baby is lying transversely or horizontally. This might commonly happen before the 26th week of pregnancy. In week 35, most babies will now flip into a head-down position.
Big and small belly
The size of your pregnancy tummy or belly does not necessarily correlate with your baby’s size. Although, it can happen, sometimes. The pregnancy belly shape and size may also fluctuate depending on the amount of amniotic fluid that surrounds your baby.
If you happen to notice an abnormality in your pregnancy tummy size, better contact your midwife or doctor ASAP.
When skin expands (and the skin on your abdomen is expanding significantly), it loses moisture, and dry skin is itchy and uncomfortable. If your butt is expanding along with your belly, it may be suffering from itch as well.
Image source: iStock
What can you do if you have an itchy belly while pregnant?
- Avoid scratching.
- Moisturize.
- Apply anti-itch cream.
- Apply vitamin E oil.
- Have a gentle oatmeal bath in warm water.
- Make use of a humidifier in your bedroom.
- For severe itching, try hydrocortisone cream.
When will a pregnancy belly bump disappear?
It takes time for the uterus to return to its pre-pregnancy size. It is no longer visible or felt through the abdomen after two weeks, and its size will be roughly back to normal after six weeks. You may experience cramping and soreness as your stomach shrinks. Breastfeeding your child can assist in the release of hormones that naturally shrink your uterus.
In general, your pregnancy weight gain, level of activity, diet, and genetics all influence how quickly your belly returns to pre-pregnancy size.
Swelling around the incision site may occur in people who have had a C-section. Scar tissue can also contribute to swelling. People who gained too much weight during pregnancy had a large fetus, or carried multiples may experience a prolonged belly.
In general, your pregnancy weight gain, level of activity, diet, and genetics all influence how quickly your belly returns to pre-pregnancy size.
But if you’re bothered about how fast or how slow your belly is growing during pregnancy, do not hesitate to ask your doctor about it.
Additional information by Matthew Doctor and Nathanielle Torre
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