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: your baby is taking up more space and your body is preparing for the birth.

Here are the main physical changes you’ll notice during the third trimester.

Physical changes

• At 7 months, the height of your uterus is about 28 cm. At 8 months, it reaches 30 cm, and then 33 cm at 9 months.
• Throughout the third trimester, you continue to gain weight, putting on about 4 kg (9 lb.).
• You may develop stretch marks on your stomach, thighs, and breasts. As your skin stretches, it can feel itchy.
• Colostrum, the fluid produced before the arrival of breast milk, may leak from your breasts.
• Your blood volume increases, which can result in anemia, a health problem characterized by low iron levels and fatigue.
• You are more flexible because your ligaments are softening and the joints in your pelvis are loosening.
• When you lie on your back, the weight of your uterus may block certain blood vessels, which can make you feel dizzy.

Common discomforts

Pregnancy affects a woman’s entire body. The cardiovascular, digestive, respiratory, nervous, reproductive, and urinary systems are all impacted. It’s therefore 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 ailment, click on its name and consult the fact sheet.

• Heartburn
• Nasal congestion and nosebleeds
• Braxton Hicks contractions
• Constipation and hemorrhoids
• Leg cramps
• Groin pain
• Fatigue
• Swelling of the legs and feet
• Pain and numbness in the hands
• Frequent urge to urinate
• Mood swings
• High blood pressure
• Insomnia or light sleep
• Back pain
• Headaches
• Vaginal discharge
• Shortness of breath
• Varicose veins in the legs
• Stretch marks

If you’re concerned about any of your symptoms, write them down and discuss them with your health care provider during your next appointment. Don’t hesitate to contact them between appointments or call Info-Santé (811) if your symptoms are worrisome. Some over-the-counter medications can relieve certain discomforts, but it’s important to talk to a doctor or pharmacist before taking any.

Things to keep in mind

• During the third trimester, you may feel more tired and uncomfortable as your belly gets bigger and heavier.
• Changes that occur in the third trimester affect your entire body.
• If you’re concerned about any of your symptoms, discuss them with the health care professional monitoring your pregnancy.

Scientific review: Roxanne Piché, nursing adviser, Maternal Fetal Medicine Clinic, CHU Sainte-Justine Research and copywriting: The Naître et grandir team Updated: June 2019