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Common Third Trimester Conditions (Including Appetite Changes)

This article covers information that you need to know about common third-trimester pregnancy conditions including appetite, constipation, edema, high blood pressure, shortness of breath/fatigue, indigestion/heartburn, and urinary tract infections (UTIs). It also covers exercise guidelines, partner support, and how to prepare for birth and the new baby.
Third Trimester
Updated: November 16, 2023
Medically reviewed by  Dr. Beth A. Pratt
Table of contents

The third trimester is dedicated to intensive fetal growth. Your baby will gain weight quickly during this period. In the final month, the heart, muscles, and bones are completely developed and essential lung and brain development finishes development.

As you approach the birth of your baby, which is considered full-term between 39 to 40 weeks, it's normal to feel equal measures of excitement and apprehension. If this is your first pregnancy, you're entering the great unknown. You may find your thoughts filled with worries about whether your baby is all right and dread about what you'll experience during labor. If you've participated in childbirth classes and have a strong partnership with your doctor or midwife, some of that anxiety will be alleviated. 

As you prepare for labor and birth, the key is to be as physically and mentally prepared as possible. If you had a healthy weight prior to pregnancy, continue to gain about one-half to one pound per week during the second and third trimester for optimal fetal growth and development.

Common Third Trimester Conditions

Basic Third Trimester Conditions

Lack of Appetite

Many pregnant women experience a decreased appetite, and cravings often disappear in the third trimester. The main reason is the pressure of the growing baby on your abdomen. There's simply less room for food.

The best way to combat this is by eating small meals every few hours. Frequent meals with small servings give your body a chance to digest small amounts of food and allow the stomach to empty quickly. To help with digestion, hydration, and waste elimination, the American College of Gynecologists and Obstetricians (ACOG) also recommends drinking 8 to 12 cups of water daily. Keep in mind that loss of appetite may also be a result of frequent indigestion or heartburn, food aversions, or ongoing occasional morning sickness.


Constipation, which afflicts many women in early pregnancy, commonly reappears in the final months of pregnancy. Frequent constipation can lead to another uncomfortable condition, hemorrhoids. A diet rich in fiber and staying hydrated can often help with constipation.

To learn more about pregnancy and bowel movements, check out Pooping and Pregnancy: A Step-by-Step Guide.


Sluggish metabolism leads to an accumulation of extra  fluid in the body tissues, which, in turn, causes edema. Edema in pregnancy may be caused by hormone-induced sodium retention, too much caffeine intake, heat, increased activity, or prolonged standing. Mild swelling, especially in your legs and feet, is typical and alone should not be considered alarming.

The American Pregnancy Association says that swelling may also be caused by:

  • Heat
  • Standing for long periods
  • Busy or active days
  • Not enough potassium intake
  • Too much caffeine intake
  • Too much sodium intake

Contact your healthcare provider immediately if you experience edema combined with headaches that don’t go away, lightheadedness or dizziness, vision problems, shortness of breath, swelling in the face or around the eyes, high blood pressure, pain and swelling in one leg more than the other, or sudden swelling of the hands, feet or ankles.

High Blood Pressure

If your edema is more serious, it could be a sign of preeclampsia. Preeclampsia is a severe medical condition associated with elevated blood pressure and may occur during pregnancy or after birth. Some women may have chronic hypertension, which is high blood pressure that occurs before pregnancy or develops before 20 weeks gestation. Women who have normal  blood pressure (120/80 mm Hg or less) sometimes develop gestational hypertension after 20 weeks of pregnancy. High blood pressure can restrict blood flow to the placenta and decrease the amount of oxygen and vital nutrients available for your baby..

According to the American College of Obstetricians and Gynecologists (ACOG), risk factors for preeclampsia are:

  • Carrying multiples

  • Preeclampsia during a previous pregnancy

  • Chronic hypertension

  • Diabetes Mellitus

  • Autoimmune diseases

  • Kidney disease

  • First pregnancy

  • Being older than 35

  • A family history of preeclampsia

  • Obesity (Body Mass Index of 30 or higher)

  • Previous pregnancy complications

  • In vitro fertilization

  • Health inequities (women who are black; women who have lower income)

Shortness of Breath/Fatigue

By the third trimester, you'll be carrying a heavy and awkward load. Even in a completely healthy pregnancy, the pressure of the expanding uterus on your respiratory system can cause shortness of breath even with mild exertion. Good posture and not overexerting yourself may help make breathing easier. 

Fatigue is common during early and late pregnancy. You may experience fatigue because the body needs more energy for your baby to grow, it is uncomfortable to sleep as the uterus expands to accommodate the growing baby, or there is simply more stress during pregnancy than before pregnancy.. To decrease fatigue and improve sleep, try using a pregnancy support pillow or sleeping in a reclined chair, taking short naps, eating healthy, and limiting unnecessary activities.

Indigestion and Heartburn

You may find that the pressure from your growing baby and expanding uterus  constricts your digestive tract, forcing stomach contents back up through the esophagus. You can minimize acid reflux or heartburn by eating small, regular meals, chewing food thoroughly,  eating slowly, and eating your last meal 2 to 3 hours before lying down or going to bed. You can also try eliminating foods that cause your heartburn and sleeping with your head raised up on pillows.

If indigestion and heartburn become a frequent problem, some medication or supplements may help relieve your symptoms. However, you should always speak with your healthcare provider before taking any medications or supplements.

Urinary Tract Infections

UTIs are common during pregnancy. However, in the third trimester, they are more serious because of the potential for developing a kidney infection. Kidney infections can provoke preterm labor. If you suspect you have a UTI, contact your doctor as it can only be treated with antibiotics.

Signs of a UTI may include:

  • Frequent urination or constantly feeling like you need to go
  • Pain or burning sensation when you urinate
  • Blood in your urine
  • Cloudy or dark urine
  • Pelvic pain

Signs of a Kidney infection include all of the above plus:

  • Side or back pain
  • High fever
  • Chills or shaking
  • Nausea and vomiting

Find out more about urinary and vaginal problems that can occur during your pregnancy from Dr. Chloe Zera of Brigham and Women's Hospital in Boston.

Exercise Guidelines

Third Trimester Exercise

Exercising while pregnant has multiple benefits to both you and the baby! It can decrease the risk of  potentially serious complications, such as high blood pressure that can lead to preeclampsia, relieve constipation,  reducestress, and improve sleep. . Exercise during pregnancy may also allow you to maintain a healthy weight and prevent some of the aches and pains associated with pregnancy, such as back pain and stiff muscles.

However, pregnancy is a different experience for each individual, so it is best to approach your exercise program with care and attention to both form and function. You should always discuss your exercise plans with your healthcare provider, even if you were working out pre-pregnancy. In most cases, it is recommended to carry on with light workouts such as walking and yoga throughout your third trimester of pregnancy.

It is common for women towards the end of pregnancy to feel short of breath, especially when exercising. Awkwardness, leg cramps, and pelvic aching can all hinder your ability to exercise as  you once did. Be mindful of your body’s abilities and rest when needed. When doing floor exercises, rise gradually from the floor to avoid dizziness and avoid lying flat on your back during the third trimester.

More: Prenatal Strengthening and Toning Exercises

How to Be a Supportive Partner During the Third Trimester

As your partner's pregnancy progresses, be aware of your own stress triggers. A recent study showed that men gained an average of three to four pounds during their partners' pregnancies. In addition, first-time fathers tended to eat and drink too much in response to stress. Lend your partner an ear so they can discuss any concerns or worries they may be having, which may increase as your baby’s due date looms near.

Pick up some extra chores around the house without being asked and cook some delicious and nutritious meals that cater to her food cravings and ensure you are both eating well.

Be a supportive and active teammate and offer to go to doctor visits with her and learn important health information about pregnancy and newborns together.

Pre-Birth Checklist: How to Prepare for Birth and a New Baby

Perineal Massage

Third Trimester Massage

Your body is making lots of new hormones that enhance the relaxation and elasticity of your muscles. This elasticity allows your abdomen and pelvis to accommodate the rapidly growing baby. If you are a first-time mom, you may benefit from stretching the vaginal opening to ease the delivery of your infant's head and minimize the need for an episiotomy. If you have had a vaginal delivery, perineal massage may decrease the risk of post-partum perineal pain.

To perform perineal massage, recline comfortably, either on your bed or the floor. Place a small amount of warm almond or olive oil on your thumb. Insert your thumb into the vagina and gradually apply light pressure downward toward your feet. Do this for a count of 10, then allow another count of 10 for relaxation. Repeat five to six times. Practice this stretching routine up to once a day in the third trimester and invite your partner to participate.

Yoga and Meditation

Participating in yoga, gentle stretching, and meditation can relieve some of the third-trimester aches and pains, improve sleep, decrease stress, and help prepare you for birth by keeping your body strong. Look for yoga classes or videos geared explicitly towards pregnancy and women’s health.

Breathing Exercises

If you took Lamaze classes, continue practicing your breathing exercises. Oxygen helps calm us and keep us focused. Deep, full breaths from your abdomen can calm anxiety and relax your body. Try placing your hands on your abdomen to focus the breath there and count slowly to ten as you breathe in, hold it for a few counts, and then breath out, counting down from ten.

Breastfeeding Prep

If you plan to breastfeed or pump breastmilk and use bottles, begin doing your prep work. See if your hospital or birthing center has a lactation consultant that will meet with you after birth. Ensure you have the needed supplies such as a nursing pillow, breast pads, a pump, storage containers, nipple cream, and breast shields.

Most insurance companies will fully or partially cover a breast pump, so contact your insurance carrier to discuss coverage options. If you plan to breastfeed, you should plan on eating a similar diet to your pregnancy one. Your breast milk provides your baby with important nutrients, so stock up on fresh fruits and veggies, whole grains, calcium, and vitamin D-rich foods.

Are you in your first or second trimester? Check out First Trimester Basics and Second Trimester Basics!

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L. Elizabeth Forry

About L. Elizabeth Forry

L. Elizabeth Forry is an Early Childhood Educator with 15 years of classroom… Read more

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