How Your Baby Bump Grows Week by Week

The moment you discover you’re pregnant, your thoughts and attention become focused on your belly. There’s something comforting about snuggling with your baby bump, even before it starts to appear. Plus, you're understandably eager to see when your little baby bump shows, to find out what signs to watch out for, and to learn how your body changes along the way as your pregnancy unfolds! That's why we've created this comprehensive weekly guide to baby bump development—read on to discover how your belly might grow and expand!

When Does Your Baby Bump Start to Show?

Throughout your pregnancy, you’ll experience normal changes throughout your body, as well as to your baby bump, and your healthcare provider can help you navigate your entire journey. As the first trimester ends and the second trimester begins, the size of the uterus has increased to the point that it no longer is completely within the pelvis. So, sometime from week 13 to week 16, or even later, is when a baby bump may start to show for many women.

Keep in mind that every woman is different and every pregnancy is unique. Your baby bump may make its debut earlier or later, and that’s totally normal.

Early Baby Bump Signs

As your baby bump starts to develop, it’s exciting to follow along! Here are a few early signs that your bump is about to show.

• Your clothing starts to fit differently. One of the signs of a growing baby bump is a snug fit in your pants or tops.

• You’ve gained a little weight. Weight gain is a natural part of pregnancy, even in the first trimester. You can use our Pregnancy Weight Gain Calculator to track your progress using ranges suitable for someone with your pre-pregnancy BMI. And, of course, always consult with your healthcare provider to ensure a healthy pregnancy, as everyone is different.

Pregnancy Belly Week by Week

While you're on the lookout for any signs of baby bump growth, your healthcare provider will monitor your progress at your regular prenatal checkups and make sure that you and your baby are staying healthy. At about week 20 of your pregnancy, the provider will start measuring the distance from the pubic bone to the top (fundus) of the uterus, which is called the fundal height measurement.

Tracking fundal height gives the healthcare provider a way to assess your baby's size and growth rate. The measurement (in centimeters) roughly equals the week of pregnancy; in week 20, for instance, your fundal height may be about 18 to 22 centimeters.

Here, we’ve set out guidelines for how your pregnant belly may grow and how your body might change week by week. You can also check out our pregnancy calendar for more details on the weeks, months, and trimesters of pregnancy.

Weeks 1 to 4: The First Moments

You won't spot any baby bump growth within the first weeks of pregnancy. Your healthcare provider will most likely calculate your due date from the start of your last menstrual period, which means that, depending on when you ovulate and when conception occurs, you may not actually be pregnant for the first week or two.

• No baby bump growth yet.

  • After fertilization, during weeks 2 and 3, your body starts producing more human chorionic gonadotropin (hCG) hormone. This prompts your ovaries to keep releasing estrogen and progesterone. (Fun fact: Many home pregnancy tests work by detecting this hormone!)

  • It may take time to adjust to the rising hormone levels, and you might experience some mood swings.

    • You may notice spotting after the embryo implants in your uterus.

Weeks 5 to 8: Early Signs of Pregnancy

Maybe your first few weeks of pregnancy went by without much change, but you may start to finally “feel” pregnant during weeks 5 to 8. Around this time, it’s common to experience some typical pregnancy symptoms like morning sickness or fatigue, but you probably won't see a baby bump emerge.

• No significant pregnancy belly growth yet, but your uterus will probably be about the size of a pear. Throughout the course of your pregnancy, your uterus will expand to 500 percent of its original volume, and there’s plenty of time for that belly to grow!

  • You may experience some early pregnancy symptoms, like nausea, heartburn, lethargy, and insomnia.

    • Believe it or not, morning sickness can be considered an indication that your pregnancy is going well, so hang in there.

    • Since every pregnancy is different, you may not experience any nausea, and everything will still progress as it should (lucky you!).

  • As your uterus grows, it will start to put pressure on your bladder and might cause you to pee more often.

Weeks 9 to 12: Your Changing Shape

Once you enter 9 weeks of pregnancy, you officially have a little fetus growing inside you! At this point, you may be wondering when your baby bump will start to show. Keep an eye out on your profile and see if you notice any slight weight gain or growth above your pelvis. By the time week 11 or 12 arrives, you may have gained around 1.5 to 4.5 pounds. But no need to worry if you’ve gained more or even lost weight. Everyone is different, and morning sickness and food aversions can impact early weight gains and losses.

• There’s potential for baby bump growth, but probably nothing too significant. The biggest change that you may notice is weight gain, which is normal at this stage.

  • Along with a growing belly may come some emotional changes, too. Adjusting to your new body shape typically takes time, especially when you start to store fat in your lower waist. This fat is needed for your pregnancy, but it can be emotionally challenging.

    • Keep in mind that body image can impact the way you feel, and that it’s normal to have a lower libido. But it’s also normal to want to have sex while pregnant, too.

  • Any standard early pregnancy symptoms, like nausea, vomiting, and fatigue, tend to peak during this time.

Weeks 13 to 16: A Little Baby Bump

At this time during your pregnancy, you've reached the second trimester. It's often considered the “honeymoon period” of pregnancy as many women feel their best during this trimester. You might notice that your baby bump is starting to show, as your baby is growing quickly. You may feel less worried and more confident now, given that the risk of pregnancy loss drops after the first three months. You might even be ready to start sharing the news! There are many creative ways to announce your pregnancy if and when you’re ready.

At about 14 weeks, your baby's reproductive system is shaping up. But when it comes to a baby boy vs baby girl belly bump, there’s not much difference in terms of belly shape or growth. What can impact the shape or size of your baby bump is the weight and positioning of the fetus, not the gender. For example, if the fetal position is slightly sideways, your pregnancy belly may appear wider rather than longer.

• You may see more baby bump growth this month, such as in weeks 15 or 16. You may want to snap a pic each week to compare the difference week to week. You may have to start shopping for some looser clothes as your belly expands.

  • You might find that morning sickness and other uncomfortable symptoms start to lessen. And with higher energy levels, you may feel a little more productive.

  • As your uterus grows, it will start to change position, sitting higher and more forward. You might begin to stand differently, which happens when your center of gravity is shifting.

  • A growing uterus also puts tension on muscles and ligaments, so some discomfort in your lower abdomen is normal. Your body is making room for your developing baby!

  • Changes to your skin are also common during these weeks. Throughout your pregnancy, your body produces more melanin, the pigment that gives color to skin. Skin darkening can occur, including the linea nigra, a dark line that runs down your abdomen.

Weeks 17 to 20: The Halfway Mark

At this point in your pregnancy, your baby will experience quite a bit of development, and you may see the same with your bump! You might even start to feel your baby move and kick—a joyful experience and a sign that all is well. At week 20, you’re basically at the halfway mark of your pregnancy. You can start to track your baby bump as your healthcare provider begins to monitor fetal development by taking fundal height measurements.

• Your uterus will expand all the way to your navel, so unless you are quite tall and your belly is stretched due to your height, you’ll most likely notice that growing baby bump!

  • Tiny flutterings in your stomach that seem like “butterflies” may be your baby moving around! These little movements tend to become stronger and more regular as your pregnancy progresses.

  • With an expanding uterus, you might feel off-center or clumsy, and some back and lower abdomen pain is common.

    • As your ligaments stretch to accommodate your pregnant belly as it grows, you might feel a sharper pain or cramp. This may last several minutes, and you may find some relief by changing position or by not moving at all. This stretching isn't harmful for you or your baby, but be sure to consult with your healthcare provider if you experience pain regularly or if you have any concerns about what you're feeling.

  • More skin darkening may occur, including on your nipples and face.

  • By week 18, your belly bump is certainly bigger as weight gain continues. Adding about one pound a week at this point is normal.

Weeks 21 to 24: Faster Baby Growth

As you make your way through the second trimester, you might notice your baby bump expanding by the week! During this month, your baby is growing at a faster pace than before, and at the same time, your hormones are starting to level out.

• Your bump is likely developing along with your baby. Gaining about a pound a week is normal.

  • Your mood swings might start to settle down, but you may also feel a little nervous as your pregnancy moves along or as you cope with body changes. It’s totally normal to have these feelings!

  • Some aches and pains are quite common, especially in the lower back and abdomen.

Weeks 25 to 28: Prepping for Labor

You’re edging closer to the third trimester, the final stretch of your pregnancy! If you don’t think you have much of a pregnancy belly yet, that may change quickly. Your baby is developing rapidly at this point—most baby development (in terms of size) occurs in the final trimester—which can cause some body changes for you, too. You may feel more kicking and even experience Braxton Hicks contractions, which are often referred to as practice contractions or “false labor.” This is a good sign that your body is preparing for labor!

• By the end of 28 weeks of pregnancy, your baby bump may measure around 28 centimeters (11 inches), according to fundal height estimates.

  • Even early in your third trimester, you might start to feel Braxton Hicks contractions. These are one way your body practices for labor, working your muscles to build strength.

  • Your uterus will expand to the midpoint between your belly button and breasts. Although it may seem as if there’s no more room to grow, part of the beauty of pregnancy is watching your body do amazing things!

  • Your baby might start to stretch and wiggle around a bit more, so you may feel some movement.

  • No need to worry if you’re gaining weight. Not only is it normal, but it’s also important! Weight gain at this point is mostly from your developing baby, growing placenta, and increased fluids in your body.

Weeks 29 to 32: Pregnancy Glow

Your due date is inching closer, which makes this month quite exciting for you and your baby bump. The third trimester might bring about some new body changes, as your baby bump is expanding and putting more pressure here and there.

• Your uterus continues to get bigger this month, moving up toward the bottom of your rib cage. You might experience more Braxton Hicks contractions.

  • It’s common for some swelling to occur, especially swollen feet and hands, often accompanied by minor pain. Your hands may even develop carpal tunnel symptoms, such as numbness or tingling, which typically subside after any swelling goes down.

  • This month, you might experience some of that “pregnancy glow” everyone talks about, particularly with your hair. This is when your hair cycle speeds up, and your mane may be fuller and thicker.

  • It’s typical to experience some itchiness or redness on your abdomen or on other parts of your body.You may also notice some stretch marks developing on your breasts, stomach, or other areas.

  • You may start to feel anxious as you look ahead to giving birth and becoming a parent. This is when the nesting instinct could kick in. You may find that doing something practical to prepare for your little one's arrival can help ease any worries.

Weeks 33 to 36: Getting Into Position

Your baby may arrive soon, and your baby bump probably gives it away. If you’re having multiples, expect your belly to be bigger, as it’s a snuggly home to more than one! Because of this growth, late-stage pregnancy can be a bit uncomfortable, but, soon enough, it’ll all be worth it.

If the nesting urge didn’t get you last month, you may experience it more at this point in your pregnancy. Nesting is not just a myth, and it can help you alleviate any stress or anxious thoughts as that baby bump grows. For any physical discomforts, stretching and light exercise, like prenatal yoga, go a long way.

• Sometime soon, your baby will "drop" into position to prepare for delivery. You may notice your baby bump shifting downward.

  • As your baby moves down toward the birth canal, you might even feel some relief in your upper abdomen, but there could be more pressure on your pelvis and bladder. If your baby doesn’t assume into the typical birthing position (head down, legs up), your bump could be a bit wider or top heavy!

    • A top-heavy pregnancy belly is more common if your baby is breech (bottom or legs down and head up) in your belly.

    • As your baby moves into position, you might also notice some relief in digestive symptoms such as heartburn or constipation.

  • This month is an important weight-gaining period for your baby, so no need to worry if you see four or more extra pounds on the scale.

  • You may discover some other changes appearing on your skin during these weeks, which can range from varicose veins or vascular spiders to dryness and itchiness on your stomach.

Weeks 37 to 40: Almost There

Although an “at term” pregnancy can last 40 or more weeks, passing 39 weeks of pregnancy is the official mark of a full-term pregnancy. If your little one prefers to stay in the coziness of your belly a bit longer, your healthcare provider will keep track of vital signs to make sure all is well.

At this time, you probably need to rest and put your feet up, but you might also feel the urge to put any finishing touches on baby preparation, from decorating the nursery to shopping for all things baby. Downloading the Pampers Club app is a great way to get all the essentials (like diapers and wipes) and earn rewards for any purchases.

• Before you became pregnant, your little uterus weighed just about two ounces. Throughout the months of your pregnancy, your body stretched, adjusted, and expanded to create a baby bump (room for your developing baby). At this time, your uterus probably weighs about 2.5 pounds!

  • At 40 weeks, your uterus has finished its expansion—phew!

    • You may notice your baby bump stretches all the way from the bottom of your rib cage to your pubic area.

  • Weight gain slows down as you near labor, so you might notice that you haven’t gained weight this month, or even lost some weight.

  • These final weeks can be challenging emotionally. You may feel tired of being pregnant or anxious for your baby to arrive. Keeping busy with a hobby or nesting are great distraction strategies. Remember, you’re almost there!

The Bottom Line

Tracking your baby bump by week can be an exciting part of your pregnancy journey. Knowing when your baby bump starts to show is part of the fun! If you’re just starting off, here's where you can get a rough idea about how far along you are in your pregnancy.

There are plenty of ways to prepare for the experience of being pregnant, like learning how to cope with pregnancy fatigue or studying up on the ABCs of pregnancy pains. If you have yet to settle on a name for your little one, get inspired with our Baby Name Generator.