Third trimester: Physical changes and common discomforts

The big day is just around the corner, and you’re filled with anticipation. But you’re also tired and increasingly uncomfortable as your belly gets bigger and heavier. All this is normal, since your baby is taking up more space and your body is preparing for birth.

What physical changes occur during the third trimester?

Here are the main physical changes you’ll notice during the third trimester (week 29 up to delivery).

• The height of your uterus (in centimetres) corresponds roughly to the number of weeks pregnant you are, give or take 2 cm. Toward the end of pregnancy, the height of the uterus stops increasing, as the fetus descends into the pelvis.
• You continue to gain weight. During the third trimester, you may gain between 225 and 500 g (0.5 to 1 lb) per week. Weight gain can vary, however, from one woman to another and from one pregnancy to another.
• Your skin stretches, which may cause stretch marks to appear on your stomach, thighs, or breasts. As your skin stretches, it can feel itchy.
• Some colostrum may leak from your breasts.
• Your blood volume increases. This can lead to anemia, a health condition caused by iron deficiency. Anemia can cause fatigue.
• You become more flexible because your ligaments are softening and the joints in your pelvis are loosening up.
• You may feel dizzy. This is caused by the weight of your uterus, which blocks certain blood vessels when you are lying on your back.

What are some common third-trimester pregnancy discomforts?

Pregnancy affects a woman’s entire body. The cardiovascular, digestive, respiratory, nervous, reproductive, and urinary systems are impacted. That means it’s normal to feel various aches and pains over the next few months.

Below is a list of the most common discomforts experienced in the third trimester. To learn more about a specific discomfort, click on its name and consult the fact sheet.

• Back pain
• Braxton Hicks contractions
• Constipation and hemorrhoids
• Fatigue
• Frequent urge to urinate
• Groin pain
• Headaches
• Heartburn and acid reflux
• High blood pressure
• Insomnia or light sleep
• Leg cramps
• Mood swings
• Nasal congestion and nosebleeds
• Numbness and pain in the hands (carpal tunnel syndrome)
• Shortness of breath
• Stretch marks
• Swelling of the legs and feet
• Vaginal candidiasis (yeast infection)
• Vaginal discharge
• Varicose veins in the legs

Some over-the-counter medications can relieve certain third-trimester discomforts, but be sure to speak to your prenatal care provider or pharmacist before taking any.

If you’re concerned about any symptoms, make a note of them and discuss them with your prenatal care provider. Feel free to contact them between appointments. You can also call Info-Santé 811 if you have any concerns.

Things to keep in mind

• During the third trimester, you may feel more tired and uncomfortable as your belly gets bigger and heavier.
• The changes you experience during the second trimester become more noticeable and affect you more during the third trimester.
• If you’re concerned about any of your symptoms, discuss them with your prenatal care provider.

Scientific review: Paméla Farman, M.Sc., nurse clinician and lecturer at the Université Laval faculty of nursing Research and copywriting:The Naître et grandir team Updated: May 2026

Photo: iStock.com/lostinbids