What changes occur during the third trimester of pregnancy?

Dr. Deborah Raines, MSN
Nursing Specialist

Twenty-eight weeks is the beginning of the third trimester of the pregnancy:

  • The fetus is now viable or able to live outside of the uterus with the technology available in the NICU. But the best home for the fetus is the uterus for another 12 weeks.
  • The healthcare provider might have the woman begin to do daily fetal activity checks or fetal kick counts, to assess the fetus' well-being.
  • It is also time to begin childbirth classes and making plans for the birth.

At 30 weeks the woman experiences a number of symptoms related to the pregnancy hormones and the increasing size of the fetus. These symptoms include:

  • Stronger fetal activity: Sometimes the movement is a strong punch or kick, other times it is a wiggle or stretch. Fetal activity often increases after meals or when the woman is relaxing or lying down.
  • Flatulence: The growing uterus places pressure on the rectum which can lead to uncontrollable passing of gas.
  • Constipation: The growing uterus and pressure on the intestine can slow bowel function resulting in constipation.
  • Bleeding gums: The pregnancy hormones and increased blood flow can result in gums that are swollen, inflamed, and even bleeding.
  • Stretch marks: As the skin stretches to accommodate the growing uterus, pink or red streaks known as stretch marks become visible.
  • Mild swelling of ankles and feet: The presence of swollen or puffy ankles and feet are a result of the increased pressure in the abdominal area.
  • Fatigue: The growing fetus is putting more demands on the woman’s body, and interrupted sleep may result in increased levels of fatigue.


The third trimester of pregnancy is very taxing on your body. Toward the end of your pregnancy, your pelvic joints feel loose, your back aches and your movements are cumbersome. Even getting out of a chair takes a little time. It is one of nature's great designs that by the end of nine months, most women are tired of being pregnant and looking forward to delivery.

During the third trimester of your pregnancy, your body might react to your rapid weight gain with stretch marks and varicose veins—you are more likely to develop both of these if your mom or grandmother did.

Here are some other changes you might expect:

  • Swelling in the feet and ankles
  • Leg cramps – often presented as sharp pain in the calves
  • Excess gas and heartburn – due to relaxing muscles in the rectum and esophagus
  • Breast growth – may also experience leaking colostrum (a pre-milk liquid)
  • Braxton-Hicks contractions – normal and harmless “practice” contractions that arrive in preparation for labor
  • Restless legs syndrome – a decrease in caffeine intake or an iron supplement can help
  • Weight gain – between one and two pounds per week
  • Difficulty breathing – thanks to the tightening of the abdomen
  • Rapid nail and hair growth

Following these changes, you may also notice symptoms of the "bloody show,” which includes a heavier vaginal discharge that may be tinted with blood or mucus. This is caused by the unlodging of the mucosal plug that blocks the entrance of your cervix to prevent infection. These are all signs that delivery may be a few days away.

Your water could also break when the membranes that hold amniotic fluid rupture, but this does not always happen before labor begins. Contact your doctor if you think you are going into labor.

Boston Women's Health Book Collective
Administration Specialist

In the third trimester, your baby is growing a tremendous amount. Your belly—and for some of us, other body parts—will be getting very big.

Your growing belly may elicit comments from well-meaning others who have opinions about your size relative to other pregnant women.

Many people like to touch big pregnant bellies, and sometimes they do so without asking permission. Most of the time, people's intentions are loving and they are reaching out toward your belly because seeing it has brought them joy. However, it is your body and you have the right to decide who can touch it. Women have very different feelings about this.

Your baby's movements become stronger as well. You may feel full-body movements as opposed to the flutters of the second trimester. You may also be able to distinguish body parts. Your partner or others will be able to feel the baby move if they can catch the right moment.

The increased size and weight of the baby can bring about other changes as well. You may feel the baby's head on your pubic bone or bladder (leading to increased frequency of urination). As your ligaments loosen in preparation for birth, you may also experience backaches and pain with walking.

Our Bodies, Ourselves: Pregnancy and Birth

More About this Book

Our Bodies, Ourselves: Pregnancy and Birth

Dr. Hilda Y. Hutcherson, MD
OBGYN (Obstetrician & Gynecologist)

In your third trimester of pregnancy, you can expect the following changes:

  • Your body will get larger, making sex more awkward.
  • Fatigue, back pain, breast leakage and hemor­rhoids can all make you feel uncomfortable and unsexy.
  • Your vagina may swell as the baby’s head drops and you may feel pressure in the area.
  • You may experience some pink spotting after in­tercourse because of this swelling. While this is usually not a problem, you should contact your healthcare practitioner if it occurs.
  • Orgasms may become more elusive.




The Good in Bed Guide to Sex and the Baby Years

More About this Book

The Good in Bed Guide to Sex and the Baby Years

Available at a substantial discount for a limited time only, thanks to support from K-Y(R) Brand!Once you get down to the business of baby-making, the advice will pour in: books, magazines, in-laws, you name it - everyone will have something to say! But there's one thing that nobody will be talking about: your sex life--how it will change, and why you should cling to it, as passionately as you'll cling to that new bundle of life with the big eyes and winning smile.That's where this book comes in. Dr. Hilda Hutcherson, MD is a distinguished OB/GYN, an author of numerous best-selling books on the subject of sexual health, a candid advocate of healthy sex on shows such as Oprah, and, most importantly, a wife and mom of four - this lady knows what she's talking about!From the pressures of conceiving, to the fumblings of pregnancy sex, to the exhaustion of baby boot-camp and the ongoing trick of not letting your new identities as parents subsume your identity as a couple, having a baby isn't just an event, it's a milestone: a series of events that signifies a true transition into adulthood and marks a clear division between then and now. Available at a substantial discount for a limited time only, thanks to support from K-Y(R) Brand "Sex and the Baby Years" is about navigating that milestone - going in one way, and coming out changed on the other end. But also staying connected and loving throughout the process.About This Author:A graduate of Stanford University and Harvard medical School, Dr. Hutcherson is presently a Clinical Professor of Obstetrics and Gynecology and Associate Dean of Diversity at Columbia University College of Physicians and Surgeons. Hilda lives in Westchester New York, with her husband and four children.Dr. Hutcherson's commitment to women's health is evidenced by her monthly women's health column in Redbook Magazine where she is also a contributing editor. She is a frequent contributor to Essence Magazine, where she had a monthly column for eight years. She is a frequent invited speaker on Women's Health and Sexuality, and has appeared on many national television programs, including Oprah, the Racheal Ray Show, the TODAY Show, Good Morning America, the CBS Early Show, 20/20, Dr. Oz and others. Dr Hutcherson is the author of three books, including the best-seller: "What Your Mother Never told You About Sex."

You're in the home stretch! Some of the same discomforts you had in your second trimester will continue. Plus, many women find breathing difficult and notice they have to go to the bathroom even more often. This is because the baby is getting bigger and it is putting more pressure on your organs. Don't worry, your baby is fine and these problems will lessen once you give birth.

Some new body changes you might notice in the third trimester (week 29 through week 40) include:

  • Shortness of breath
  • Heartburn
  • Swelling of the ankles, fingers and face. (If you notice any sudden or extreme swelling, or if you gain a lot of weight really quickly, call your doctor right away. This could be a sign of preeclampsia.)
  • Hemorrhoids
  • Tender breasts, which may leak a watery pre-milk called colostrum
  • Your belly button may stick out
  • Trouble sleeping
  • The baby "dropping", or moving lower in your abdomen
  • Contractions, which can be a sign of real or false labor

As you near your due date, your cervix becomes thinner and softer (called effacing). This is a normal, natural process that helps the birth canal (vagina) to open during the birthing process. Your doctor will check your progress with a vaginal exam as you near your due date. Get excited—the final countdown has begun!

This answer is based on source information from the National Women's Health Information Center.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.