First Trimester of Pregnancy: Body Changes

During the first trimester, your body will go through a lot of changes, while your baby is developing. As your hormone levels change and your baby starts growing, so will your body. The changes are more than just your belly though; expect to feel different in many ways as you progress through the first trimester.

Belly changes

Your belly may change slightly during the first trimester, but not as much as during the next two trimesters. Your baby is still very small, so most of your belly changes are from the weight you gain in your first trimester. Most physicians recommend gaining about 3-6 pounds during the first trimester and eating approximately 150 extra calories a day from healthy sources.

Breast changes

Your breasts will change in multiple ways during the first trimester. Expect to have some breast tenderness due to the mammary glands enlarging. Your breasts can grow and become tender as your breasts begin preparing for breastfeeding. This also occurs from a rise in progesterone and estrogen. The areolas around your nipples may also show changes, by becoming darker with larger Montgomery tubercles bumps. Veins can also become more visible.


Fatigue is very common in the first trimester. Don’t be surprised if the physical changes in the first trimester cause extreme tiredness and fatigue, requiring extra rest. Don’t worry, the extreme fatigue you may experience in the first trimester dissipates in the second trimester for most women.

Heartburn and digestive problems

The increased hormones in your body during pregnancy also create some digestive problems and heartburn. Nausea is most common during the first trimester and can range from mild nausea to vomiting daily. You may also experience some constipation, heartburn, and problems digesting food properly. Try eating smaller meals throughout the day and avoiding acidic, spicy, and greasy foods. Like the fatigue experienced in the first trimester, the morning sickness and nausea go away in the second trimester for most women.

Increased urination

While increased urination is more common in the third trimester, it can also occur during your first few months of pregnancy. Don’t be surprised if you find yourself using the restroom more often as your uterus is growing which puts pressure on your bladder.


Mild spotting and some bleeding is normal in the first trimester and occurs in about 1 in every 4 women. It typically isn’t a concern unless it is heavy bleeding and accompanies severe cramping. Spotting occurs shortly after the fertilized embryo implants in your uterus.

Mood changes

Finally, be aware of possible mood changes, which are also due to the change in hormone levels. This can cause mood swings and irritability, similar to what you may experience shortly before your menstrual cycle.

The physical changes occurring in your first trimester may seem uncomfortable, but they are a sign your pregnancy is progressing normally and can actually be a good sign.

Read More:
What Happens in the First Trimester of Pregnancy With My Body?
What Happens in the First Trimester of Pregnancy With My Baby?
What Happens in the First Trimester of Pregnancy with Doctor's Appointments and Tests?