What to Expect During Pregnancy:

Third Trimester

The third trimester of pregnancy can often be the most challenging for women. As the baby finishes growing, your body begins preparing for delivery and many of the light affects of pregnancy during the second trimester make way for more intense changes.

Contact your doctor if you experience:

  • Bleeding (this could signal preterm labor or other serious problems)
  • Severe dizziness, abdominal pain, cramps, nausea, or vomiting
  • Rapid weight gain or too little weight gain
  • Pain or burning during urination (this could be a sign of a urinary tract infection)

Changes in your body during the third trimester

During the third trimester, your body can undergo the following changes:

Breast enlargement

Close to the baby’s due date, your breasts will have become enlarged and may begin discharging a yellowish substance from the nipples. This is called colostrum, which will nourish the baby during the first few days of life. Breast enlargement can cause back pain, so it’s important to wear a supportive bra.


Mild swelling due to water retention may occur in the ankles, hands and face during the third trimester. Elevating your feet when sitting or sleeping can be helpful. If you experience sudden swelling, call your doctor right away – it could mean a pregnancy complication called preeclampsia.

Related resource: Preeclampsia handout

Weight gain

It is normal to gain ½ to 1 pound a week during your last trimester (consult with your doctor about your target weight gain range). This weight includes the baby’s weight, placenta, breast tissue, increased blood flow, amniotic fluid and other fluid.

Symptoms & side effects

During the third trimester, you may also experience:


From all the extra weight put on through pregnancy, your back may feel sore or achy. Additionally, your pelvis and hips may also feel uncomfortable due to the ligaments loosening in preparation for labor. To ease achiness, sit up straight, sleep on your side with a pillow between your legs, wear comfortable shoes, and use a heating pad on the achy area (as needed).


Fatigue is a common experience during the last few months of pregnancy, caused by carrying extra weight, difficulty sleeping, and emotional aspects of preparing for the baby’s arrival. Exercising, eating healthy, napping and taking time to relax can help maintain your energy through the day.

Frequent urination

The baby becomes much larger during the last trimester and can put a lot of pressure on your bladder. This causes the need to urinate much more often than usual, including throughout the night (which can also cause fatigue). Additionally, leaking may occur when you laugh, sneeze, cough or exercise. Wear a panty liner to absorb leakage, and limit fluid intake before bed to keep nighttime bathroom trips at a minimum.

Shortness of breath

As the baby grows, the uterus rises to the bottom of the rib cage, taking up some of the space where the lungs normally expand. This can cause shortness of breath. Propping your head and shoulders up at night and exercising can help with difficulty breathing.


Increased production of the hormone progesterone can stimulate the esophagus, which helps keep food and acids down, to relax. This can cause acid reflux (heartburn). Waiting to lie down after meals; eating smaller, more frequent meals; and avoiding greasy, spicy or acidic foods will help you avoid heartburn.


Extra progesterone can also cause constipation. Introducing more fiber and liquids into your diet will help symptoms.

Braxton Hicks contractions

Toward the end of your pregnancy, you may begin to feel slight or intense contractions as you near your delivery date. These are called Braxton Hicks contractions, which may lead to labor and actual contractions – marked by an increase in intensity and frequency. If you feel regular and intense contractions, you may be in labor and should call your doctor.


Close to your due date, you might have a clear, thick, or blood-tinted discharge that indicates the cervix has begun dilating for labor. If this flow is heavy and soaks through a panty liner, you should call your doctor. A large amount of sudden discharge probably means your water has broken, signaling the beginning of labor (this does not often happen before contractions begin).


Abnormally low blood cell or hemoglobin (a protein that contains iron) levels can slow the baby’s growth or induce preterm labor. Iron supplements can help treat anemia.

Gestational diabetes

A pregnant woman may develop diabetes during pregnancy that lasts until after the baby is born. Monitoring blood sugar levels and healthy eating habits will help manage gestational diabetes.


Veins around the anus can become swollen and discolored (varicose veins) during pregnancy as extra blood begins flowing and the uterus grows and puts pressure on surrounding areas. Hemorrhoids can itch and cause discomfort. To relieve symptoms, it helps to sit in a warm bath. If hemorrhoids become problematic, ask your doctor if you should use hemorrhoid ointment.

Varicose and spider veins

Varicose veins are blue, swollen veins caused by pressure from the abdomen. If varicose veins appear, you can prevent them from worsening by moving throughout the day, propping your legs up when sitting for long periods and wearing support hose.

Thin red veins – called spider veins – may also develop due to increase blood flow. These tend to get worse during the third trimester, but both spider and varicose veins usually clear after the baby is born.