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Pregnancy - third trimester
Medical expert of the article
Last reviewed: 06.07.2025
The third trimester of pregnancy lasts from week 28 until the baby is born. The doctor will calculate a specific due date (40 weeks), but the baby is considered full-term if it is born between 37 and 42 weeks. During the third trimester, the fetus gains weight and all its organs mature. It moves more often, especially between 27 and 32 weeks.
In the last two months of pregnancy, the fetus becomes too large, making it difficult for it to move in the uterus. By the end of the third trimester, it turns head down, causing discomfort. This is a sign that the due date is approaching.
[ Characteristic signs of pregnancy in the third trimester
- Braxton Hicks contractions (painless contractions of the uterus, a kind of preparation for childbirth, but they do not provoke the opening of the cervix and the onset of labor).
- Fatigue
- Back pain
- Pain in the abdomen and side
- Hemorrhoids and constipation
- Heartburn
- Carpal tunnel syndrome
- Difficulty breathing because the uterus is located under the rib cage and the lungs do not have enough room to breathe in.
- Minor swelling of the legs and ankles, as a lot of fluid accumulates in the body during pregnancy and the uterus creates additional pressure.
- Sleep disturbance and inability to find a comfortable position during rest. Resting on your back slows down blood circulation, and turning over onto your stomach is impossible. Sleep on your side, put a pillow under your stomach. Later, it is best to lie on your left side, since lying on your right side or back increases the mass of the uterus and partially blocks large blood vessels.
- Frequent urination caused by the enlargement of the uterus and pressure of the fetus on the bladder.
Signs of approaching labor
The fetus turns head down and descends (but the woman does not always feel this).
The cervix becomes thinner and begins to open. The doctor usually does an examination and determines the degree of opening.
Braxton Hicks contractions become more frequent, intense and somewhat painful. There is also constant lower back pain.
The amniotic sac ruptures. In most cases, the rupture occurs after labor begins. In some women, it happens before labor begins. Call an ambulance immediately if the amniotic sac ruptures.