Pregnancy

Third Trimester: What's Normal as You Near Birth

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The third trimester covers weeks 28 to 40 and packs the most discomfort into the shortest stretch: swelling, back pain, heartburn, breathlessness, poor sleep, and Braxton Hicks contractions. Most are normal as the baby grows and drops lower. A few signs, such as reduced movement, severe headache, or bleeding, warrant a same-day call.

Last updated: July 2026

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What happens in the third trimester?

The third trimester begins at week 28 and continues until delivery, typically near week 40. According to the Office on Women's Health, the baby gains most of its weight during these final weeks while its organs finish maturing 1. As the uterus expands, it presses on the lungs, stomach, and bladder, which explains breathlessness, heartburn, and frequent urination.

Many people feel the baby drop lower in the last weeks, easing pressure under the ribs but adding pelvic weight. Braxton Hicks contractions, irregular and usually painless, become more noticeable, and a nesting urge and disrupted sleep often round out this stage. Heartburn and shortness of breath tend to peak now, then ease slightly once the baby drops lower before birth.

Which third-trimester symptoms are normal?

Most late-pregnancy discomforts are normal responses to a full-term-size uterus. Swelling in the feet and ankles, back and hip pain, heartburn, hemorrhoids, leg cramps, and interrupted sleep are all common. Gentle movement helps, and ACOG recommends continuing about 150 minutes of moderate activity a week in an uncomplicated pregnancy 2.

Bladder leaks with coughing or laughing affect as many as 1 in 3 pregnant women, and pelvic floor training can reduce them 3. Practical relief guides on sciatica pain, hemorrhoid symptoms and treatment, and pelvic floor exercises cover the aches that dominate these weeks. Leg cramps at night and mild ankle swelling by evening are also typical in these final weeks.

How can I tell normal aches from a warning sign?

Telling ordinary discomfort from a red flag is the central skill of the third trimester. Braxton Hicks contractions are irregular, ease with rest, and do not grow stronger, whereas true labor contractions come at regular, shortening intervals. Steady swelling of the feet is expected, but sudden swelling of the face and hands, especially with a severe headache or vision changes, can signal preeclampsia 4.

Our guide to preeclampsia symptoms explains what to watch for after 20 weeks. According to NICE, blood pressure and urine are checked at every late-pregnancy visit precisely to catch these changes early 4. Reduced fetal movement is the single sign most worth acting on quickly, since patterns should stay consistent day to day.

Does the third trimester differ with age or a first birth?

Age and birth history shape the final weeks in subtle ways. A first pregnancy may bring the baby's drop, or lightening, weeks before labor, while later pregnancies sometimes see it happen only as labor begins. Pregnancy after 35 is associated with higher odds of conditions like high blood pressure, so monitoring often intensifies toward term 4.

Teen pregnancies carry their own screening priorities even when symptoms feel routine, and postpartum recovery in a sense starts here as the body prepares for birth and feeding. Regular visits often become weekly in the last month so a clinician can track growth, position, and blood pressure. Emotional ups and downs are common too, as sleep thins and anticipation builds toward the due date.

When third-trimester symptoms need your OB

Certain late-pregnancy symptoms call for prompt contact rather than waiting for the next visit. A noticeable decrease in the baby's movement, vaginal bleeding, a gush or leak of fluid, severe or constant headache, vision changes, sudden swelling, or regular contractions before 37 weeks are all reasons to seek same-day review. Painful, burning urination can point to an infection that needs treatment, and signs of labor before 37 weeks, such as regular tightening or leaking fluid, also merit prompt contact.

Most of the third trimester is simply uncomfortable rather than dangerous, but a clinician can quickly sort ordinary aches from the signs that matter. Gale can help you keep your questions and symptom notes ready for each appointment.

Common questions

Braxton Hicks are irregular practice contractions that tighten the belly and then ease, often with rest or a change of position. Unlike true labor, they do not come at regular, shortening intervals or steadily intensify.

Mild swelling in the feet and ankles is common as blood volume rises and the growing uterus slows the return of fluid from the legs. Sudden swelling of the face or hands, especially with a headache or vision changes, is different and deserves a same-day call.

True labor contractions come at regular intervals that grow closer and stronger and do not stop with rest, often with low back pain or a bloody show. If you are unsure or are before 37 weeks, a clinician can help you tell the difference.

A large belly, frequent urination, heartburn, leg cramps, and anxiety about birth all disrupt sleep in the final weeks. Side-lying positions and support pillows help many people, though persistent insomnia is worth mentioning at a prenatal visit.

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Third-trimester signs that need a same-day call

  • —A clear decrease in the baby's usual movement is a reason to seek same-day obstetric review.
  • —Severe or constant headache, vision changes, or sudden swelling of the face and hands can signal preeclampsia and is a reason to seek urgent care.
  • —Vaginal bleeding, or a gush or steady leak of fluid, is a reason to contact your obstetric clinician right away.
  • —Regular, painful contractions before 37 weeks can indicate preterm labor and is a reason to seek prompt review.

If you notice reduced fetal movement, heavy bleeding, a severe headache with vision changes, or regular contractions before 37 weeks, contact your obstetric clinician or labor unit right away or go to the nearest emergency room; call 911 for heavy bleeding with fainting or a seizure.

This article is general health education, not medical advice. Whether a third-trimester symptom is routine or urgent depends on your exam, blood pressure, and history, and that judgment rests with your obstetric clinician or midwife.

References

  1. 1.Office on Women's Health (U.S. HHS) (2025). Prenatal care. Office on Women's Health (womenshealth.gov), U.S. HHS. link ✓General framing of third-trimester fetal weight gain and organ maturation, and the physical effects of an expanding uterus.
  2. 2.American College of Obstetricians and Gynecologists (2020). Physical Activity and Exercise During Pregnancy and the Postpartum Period: ACOG Committee Opinion, Number 804. Obstetrics & Gynecology. doi:10.1097/AOG.0000000000003772 ✓ACOG recommendation to continue about 150 minutes of moderate activity per week in an uncomplicated pregnancy, including the third trimester.
  3. 3.Woodley SJ, Lawrenson P, Boyle R, et al. (2020). Pelvic floor muscle training for preventing and treating urinary and faecal incontinence in antenatal and postnatal women. Cochrane Database of Systematic Reviews. doi:10.1002/14651858.CD007471.pub4 ✓Prevalence of urinary incontinence in pregnancy and the benefit of pelvic floor muscle training for preventing and treating it.
  4. 4.National Institute for Health and Care Excellence (2024). Antenatal care (NG201). National Institute for Health and Care Excellence (NICE). link ✓Late-pregnancy antenatal monitoring of blood pressure and urine and surveillance for preeclampsia and other complications after 20 weeks.

4 sources, numbered by first appearance. General health information, not medical advice. AI-assisted editorial content — every citation independently verified. Editorial policy

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