The third trimester is the final stage of pregnancy. During this stage, the growing uterus and fetus put new demands on the body that can cause pain and discomfort.

This article looks at some common causes of pain and discomfort during the third trimester and how to alleviate these symptoms.

A woman in her third trimester of pregnancy stretches her back to relieve pain.Share on Pinterest
Discomfort during the third trimester of pregnancy may include sore breasts, swelling, heartburn, and back pain.

Third trimester pregnancy pain and discomfort can affect different parts of the body.

The following are some of the most common symptoms that can develop during the third trimester of pregnancy, along with their associated causes and treatments.

Sore breasts

Many women find that their breasts become tender or painful during pregnancy. A woman may also find that her cup-size increases.

Increased breast size and tenderness result from hormonal changes that happen in preparation for breastfeeding.


To help prevent or alleviate breast pain during pregnancy, a woman could try wearing a larger, more comfortable, and supportive bra. This may mean buying some new bras as the pregnancy progresses.

According to UT Southwestern Medical Center, wearing a bra that is too tight can prevent the breasts from producing milk.


During the third trimester, different parts of the body may swell. The feet and ankles are common sites of swelling.

Swelling, or edema, is the result of increased blood volume and associated fluid retention.

A woman’s body increases blood production during pregnancy to support the growing fetus. According to a 2014 study, total blood volume increases can range from 20% to 100% of a woman’s pre-pregnancy blood volume. The typical increase is about 45%.

As the pregnancy progresses, the uterus puts increasing pressure on the large veins that return blood to the heart. This can cause excess fluid to pool in the lower limbs.


To prevent swelling in the lower limbs, a woman should try to limit the amount of time she spends on her feet during the day. Elevating the feet when sitting can help reduce any swelling.


According to a 2010 article, heartburn refers to an uncomfortable burning feeling in the center of the chest. It is a primary symptom of acid reflux and the more severe gastroesophageal reflux disease (GERD).

The article indicates that up to 80% of pregnant women experience GERD during their pregnancy.

Heartburn can develop at any stage of pregnancy, but it is most common during the second and third trimesters. This is likely due to hormonal changes and the effects of the growing uterus and fetus pressing on the stomach.


According to UT Southwestern Medical Center, the following over-the-counter (OTC) or prescription medications are safe for women to take during pregnancy:

  • oral antacids
  • H2- receptor antagonists
  • proton pump inhibitors

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) recommend making lifestyle changes to help reduce the incidence of heartburn. These include:

  • avoiding foods that trigger heartburn
  • eating smaller meals
  • wearing loose-fitting clothing around the abdomen
  • sitting in an upright position following a meal
  • avoiding eating within 2–3 hours of going to bed
  • sleeping with the head of the bed raised 6-8 inches off the floor

Back and hip pain

Hormonal and postural changes can contribute to back and hip pain during pregnancy.

Hormonal changes

During pregnancy, levels of the hormones progesterone and relaxin increase.

Progesterone relaxes the tissues and ligaments that allow the body to accommodate the growing uterus.

Relaxin relaxes the ligaments between the pelvic muscles to enable the baby to pass through the birth canal more easily.

Progesterone and relaxin circulate throughout the body, relaxing tissues and ligaments and causing instability in the joints in other parts of the body. This can result in pain and discomfort in the back and pelvis.

Postural changes

As the fetus develops and the abdomen grows larger, a woman may find that she is shifting her weight differently. This can cause changes in posture that result in pain in the lower back, hips, and legs.


A pregnant woman should talk to her doctor before taking any pain relief medication. A doctor will be able to advise on which medications are both safe and effective.

A doctor may also recommend the following treatments to help alleviate pregnancy-related back or hip pain.

Vaginal pain or pressure

During pregnancy, a woman may experience unusual or uncomfortable sensations in her vagina.

According to the Texas Children’s Hospital, sensations of pressure or fullness in the vagina can start early on in pregnancy but may increase in the third trimester. These sensations may occur due to:

  • increased blood flow to the genitalia
  • increased pressure from the growing uterus and fetus
  • increased pressure from the head of the fetus positioning itself down in the pelvis early in the third trimester


Sensations of pressure or fullness in the vagina are usually uncomfortable rather than painful and rarely require treatment. However, any woman who develops severe vaginal discomfort or pain should talk to her doctor.

Abdominal pain

There are two common causes of abdominal pain during the third trimester of pregnancy. These are:

Increasing pressure on the abdomen

As the uterus and fetus grow, pressure in the abdomen will increase. Pressure on different organs and tissues can cause a variety of symptoms. Pressure on the stomach affects digestion, pressure on the diaphragm affects breathing, and a compressed bladder increases the urgency to urinate.

Irregular contractions

During the later stages of pregnancy, the body begins preparing for labor. A woman may have irregular contractions known as Braxton Hicks. These contractions can sometimes feel intense, but they are more uncomfortable than painful.


Most abdominal pain is mild to moderate. Anyone who experiences more severe or persistent pain should talk to her doctor. The pain could be due to an underlying condition, such as a urinary tract infection.

A pregnant woman should see her doctor if she experiences any unusual pain in the abdomen, an unusual amount of bloody discharge from the vagina, and for the following reasons:

  • swelling in the face and hands
  • excessive heartburn that does not go away following treatment with OTC or prescription medications
  • a severe headache
  • problems with vision
  • high blood pressure

The above symptoms could be a warning sign of preeclampsia. This is a potentially dangerous pregnancy complication that can threaten both the mother and the fetus.

If a woman has concerns about her safety or that of the developing fetus, she should talk to her doctor as soon as possible.

Pain and discomfort during the third trimester of pregnancy are common. This is the time when the growing uterus and fetus will be placing added demands on the body.

In most cases, the pain or discomfort a woman experiences is a normal part of pregnancy, and most people can treat it with lifestyle changes or medications.

However, any pregnant woman who experiences unfamiliar pain in the abdomen or develops any other worrying symptoms should talk to her doctor.