How the body changes during pregnancy: everything that happens month by month

Notice: the contents of this article are for informational purposes only and do not replace the advice of your doctor or midwife.

The body changes radically during pregnancy. It's not just your belly: your skin, breasts, posture, hair, mood, and even the way you breathe all change. Some changes happen right away, in the first few weeks. Others develop slowly, trimester by trimester. Knowing what to expect in advance can help you deal with them more calmly, knowing what's coming and when. 

This guide explains how the body changes during pregnancy in a comprehensive and straightforward way, without causing unnecessary alarm or glossing over the details that matter.

First trimester: the changes you can't see (but can feel)

During the first twelve weeks, the body changes a great deal, even though almost nothing is visible on the outside. The baby bump isn't there yet, but a lot is happening inside. Pregnancy hormones, particularly HCG and progesterone, rise rapidly and bring with them a range of effects that many women don't expect.

Nausea and fatigue

These are the most common symptoms of the first trimester. Nausea can be mild or severe, occurring in the morning or all day long. Fatigue is often surprisingly intense: you may feel exhausted even when you haven't done anything. Both are caused by hormones and tend to improve toward the end of the third month.

The breasts change right away

One of the very first signs of pregnancy is the breasts: they become more sensitive, fuller, and heavier. The areolas tend to darken and enlarge, and Montgomery glands—small bumps around the nipple—may appear. These changes are the body preparing for breastfeeding, long before the baby bump becomes visible.

A bra that provides good support becomes essential already at this stage: look for one without rigid elements that press against sensitive breasts and that is comfortable to wear all day.

Bloating and indigestion

Progesterone slows down digestion, causing bloating, heaviness, and sometimes constipation. Your stomach may feel full more quickly than usual. Mild cramps in the lower abdomen are also normal in the first few weeks: they are caused by the uterus beginning to expand.

Your mood changes

Hormonal fluctuations in the first trimester significantly affect your mood. You may feel emotionally unstable, more irritable than usual, or conversely, euphoric and then suddenly sad. It's all normal. The body is going through one of the most radical hormonal changes of your life and needs time to adapt.

Second trimester: the body takes shape

The second trimester begins around the thirteenth week and is the best phase for many women. Nausea subsides, energy returns, and the baby bump finally starts to show. The changes become more visible, but the body is still light enough to move with relative ease.

The baby bump grows

By the sixteenth or twentieth week, the baby bump becomes evident. The uterus moves upward, out of the pelvis, and begins to take up space in the abdomen. This changes your posture and center of gravity: the back arches slightly downward to compensate for the weight in front, and lower back pain may appear.

This is the time when regular clothes start to stop working and it's worth updating your wardrobe. To help you figure out how to dress well during this phase, take a look at the maternity size guide, which explains how to measure yourself and choose the right size.

The skin transforms

In the second trimester, the skin is one of the areas that changes the most. The increasing size of the abdomen puts the skin under tension, and stretch marks may appear: streaks that are initially reddish or purple, then lighter, forming when the skin is stretched faster than it can adapt. Not all women develop them in the same way: genetics play an important role, but a daily moisturizing routine helps prevent or minimize them.

A linea nigra may also appear, a dark vertical line running from the navel downward (or upward). It is caused by increased melanin production and tends to disappear spontaneously after birth. Some women develop melasma on their face, dark patches on the forehead, cheeks, and nose. The sun makes them darker: high-SPF sun protection is essential.

The navel changes

As the baby bump grows, the navel tends to flatten and, in some cases, protrude outward. It is not dangerous and does not require special attention. It usually returns to its normal shape after birth.

The baby's first movements

Between the sixteenth and twentieth weeks, fetal movements begin. The first times they feel like bubbles or butterflies in the abdomen. As the weeks go by, they become increasingly noticeable, until they are visible from the outside in the last trimester. For many women, this is the moment when pregnancy truly feels real.

The breasts continue to grow

The breasts continue to increase in volume throughout the second trimester. The areolas darken further, and the first drops of colostrum, the precursor to breast milk, may appear toward the end of the second trimester. This does not happen visibly in all women, and it does not mean anything in terms of your ability to breastfeed.

Third trimester: the body at its maximum change

The third trimester is when the body works the hardest. The baby bump is large, internal organs are displaced, weight has increased significantly, and movement requires more effort. But it is also the final phase, the one in which everything prepares for the baby's arrival.

Weight increases

Total weight gain in a healthy pregnancy ranges between 9 and 14 kilograms, but this is an indicative value that depends on your starting weight and many other factors. Weight is not just fat: it includes the baby, the placenta, amniotic fluid, increased blood volume, and increased breast tissue. In the last trimester, weight gain is slower because most of the weight corresponds to the baby's final growth.

The back and joints

With a large baby bump, the center of gravity shifts further forward. The back works harder than usual to maintain balance, and lower back pain becomes frequent. Pregnancy hormones, particularly relaxin, soften the ligaments throughout the body to prepare it for birth: this makes the joints less stable and more vulnerable to strain. The result is often a feeling of instability when walking, especially on uneven ground.

Heavy legs and swelling

The weight of the uterus presses on the blood vessels in the pelvis and legs, slowing circulation. The legs become heavy, and the feet and ankles swell, especially toward evening. Keeping your legs elevated, walking regularly, and wearing clothes that do not constrict are the most effective remedies. 

If you want to learn more, we have a guide dedicated to leg pain during pregnancy with causes and practical remedies.

Breathing changes

As the baby bump grows upward, the diaphragm is compressed and the space for the lungs is reduced. Many women in the third trimester experience shortness of breath, especially when climbing stairs or exerting themselves. It is not dangerous; it is simply the body adapting to the reduced space. In the final weeks, when the baby drops into the pelvis in preparation for birth, this feeling tends to improve.

Sleep becomes difficult

Finding a comfortable sleeping position with a large baby bump is not easy. From the second trimester onward, sleeping on your back is not recommended because the weight of the baby bump can compress the vena cava. The left side is the recommended position. A pregnancy pillow that supports both the baby bump and the back makes a huge difference in the quality of your rest.

The skin continues to change

Stretch marks may continue to appear or widen in the last trimester, when the baby bump reaches its maximum size. Continuing your daily moisturizing routine is important even at this stage. The abdominal skin may become itchy due to continuous stretching: a moisturizing cream helps reduce the discomfort.

The changes that surprise the most

In addition to the best-known ones, there are some changes that many women do not expect and that are worth knowing.

Hair

During pregnancy, hormones prolong the hair growth phase, reducing shedding. Many women notice that their hair becomes thicker and shinier, especially in the second trimester. The flip side comes after birth: postpartum hair loss can be more abundant than usual, precisely because all the hair that did not fall out during pregnancy falls out together in the following weeks. It is temporary, but it can frighten those who do not expect it.

Gums

Pregnancy hormones make the gums more sensitive and more prone to inflammation and bleeding. Dental cleaning becomes more important during this period, not less. It is worth informing your dentist about your pregnancy and, if necessary, scheduling a professional cleaning.

The nose

Increased blood volume and hormonal changes can cause nasal congestion and nosebleeds, even in the absence of a cold. It is called pregnancy rhinitis and is very common, especially in the second and third trimesters.

Sensitivity to fragrances and flavors

Especially in the first trimester, the sense of smell becomes significantly sharper. Scents that were previously neutral can become unbearable. Tastes also change: foods you once loved may become impossible to eat, and vice versa. It is one of the evolutionary mechanisms protecting the fetus from potentially harmful substances.

How to take care of your changing body

Knowing the changes is the first step. The second is knowing how to support them.

• Moisturize your skin every day, especially on your belly, hips, and breasts, to maintain elasticity and reduce stretch marks. Start early, already in the first trimester.
• Choose a bra that adapts to your growing breasts: without underwires, with good support, and adjustable.
• Update your wardrobe as your body changes: tight clothes restrict circulation and make everything more uncomfortable.
• Move every day: even just a walk helps circulation, reduces leg swelling, and improves sleep.
• Use high-SPF sun protection on your face to prevent melasma, especially during the summer months.
• Listen to your body: every pregnancy is different. What happens to another woman is not necessarily what will happen to you, and vice versa.

Frequently asked questions about how the body changes during pregnancy

When does the baby bump start to show?

The baby bump starts to show clearly between the sixteenth and twentieth weeks for women who are pregnant for the first time. Those who have had previous pregnancies tend to show it sooner, because their abdominal muscles have already been stretched. In the first few weeks, the abdomen may appear slightly more bloated, but it is not yet the baby bump: it is bloating caused by hormones and digestive changes.

How many sizes do breasts grow during pregnancy?

There is no single rule for everyone. On average, breasts increase by one or two sizes during pregnancy, but some women may increase by three or four. Growth begins in the first few weeks and continues throughout the first and second trimesters. In the last trimester, it tends to stabilize, then increase again after birth with milk coming in, if you are breastfeeding.

Can stretch marks during pregnancy be prevented?

They cannot be completely prevented: genetics play an important role, and some women develop them regardless of what they do. What you can do is reduce their severity with a daily moisturizing routine. A specific stretch mark serum applied daily to the belly, hips, and breasts helps keep the skin elastic and limit the formation of new stretch marks. The most important thing is to start early, already in the first trimester, and do it consistently.

Why does your belly itch during pregnancy?

Itching on the belly during pregnancy is very common and is caused by the stretching of the skin as the baby bump grows. The skin stretches and becomes drier, which causes that itchy feeling. A moisturizing cream applied regularly helps reduce it. If the itching is very intense and widespread across the entire body, especially in the final weeks, it is best to talk to your doctor because it may be a sign of a condition called cholestasis, which requires attention.

Does hair grow more during pregnancy?

In a sense, yes. Pregnancy hormones prolong the hair growth phase and reduce normal physiological shedding. The result is that many women notice thicker and fuller hair during pregnancy. In the months after birth, when hormones return to pre-pregnancy levels, more abundant hair loss than usual often occurs: it is the body recovering the hair it did not lose in the previous months. It is temporary and does not indicate a problem.