The Third Trimester: What to Expect & How to Prepare

Welcome to the home stretch! The third trimester of pregnancy begins at week 28 and continues until birth, which typically occurs around week 40 (or a few weeks later). When the third trimester starts, you’re about seven months pregnant. There’s a good chance you are experiencing some discomfort, trouble sleeping and even a return of those pesky first-trimester symptoms like nausea and fatigue. 

In this week-by-week guide, we’ll walk you through what to expect in the third trimester—physically, emotionally, and everything in between.

When Does the Third Trimester Start and End?

The third trimester of pregnancy begins at approximately 28 weeks and lasts until birth, typically around 40 weeks. However, some babies take a little longer to make their debut. The third trimester covers months 7-9.

Key Changes in the Third Trimester

Physical Changes You May Experience

Many third-trimester symptoms are simply the result of your body making space for a growing baby and preparing for birth, but that doesn’t mean it’s an easy process. From lower back pain in the third trimester to cramping and sleep disruptions, this stretch can feel physically demanding. Here are some physical changes you may notice:

• Lower back, pelvis and joint pain
  
• Belly pains
  
• Swelling in the legs and ankles
  
• Fatigue
  
• Shortness of breath
  
• Frequent urge to urinate
  
• Nausea and vomiting
  

Emotional Changes to Expect

You won’t just change physically; many women experience a range of emotional changes as well. It’s not uncommon to have:

• Mood swings
• Increased anxiety and stress
• Nesting instincts

Common Symptoms & Discomforts in the Third Trimester

Unlike the second trimester, often referred to as the “golden trimester,” this trimester has its fair share of symptoms. Your body’s preparing to give birth, and your baby is nearly full-size, so you may experience some discomfort and other symptoms as your body makes room for the growing fetus.

Braxton Hicks Contractions

Also known as prodromal or false labor pains, these "practice" contractions can feel like tightening across your belly. How to tell difference between braxton hicks and contractions? Unlike real labor, they’re irregular and usually not painful. There’s no medical treatment, but you can find some relief by adjusting your sitting or lying position and ensuring you stay adequately hydrated.

Third Trimester Swelling & Water Retention

You may have swollen legs and ankles due to the increased blood volume and fluid retention. While some swelling is inevitable, you can help alleviate it with adequate hydration and frequent breaks (avoid standing or sitting in one position for too long). 

Heartburn & Digestive Discomfort

Heartburn is a prevalent pregnancy symptom that often intensifies further into your pregnancy. In fact, about 25% of pregnant women experience daily heartburn during pregnancy, and many report severe heartburn in the third trimester. Hormonal changes and increased stomach pressure from your enlarged uterus are usually the cause. Similarly, pregnancy indigestion, like bloating, gas and discomfort after eating, is common during this stage of pregnancy. While minor dietary adjustments (like avoiding spicy or fatty foods and eating smaller meals) can help support digestion, it’s important to speak with your healthcare provider if your symptoms become severe or interfere with eating and sleep.

Sleep Disruptions

Between the frequent urge to urinate, joint and lower back pain and an active baby with a different sleep schedule, you may have difficulty sleeping in the third trimester. You can try a different sleeping position, like sleeping on your left side. You can also try extra pillows and gentle stretching to find relief.

Shortness of Breath

As your uterus grows, it pushes against your diaphragm, making it harder to take deep breaths. This is normal; about 60-70% of healthy pregnant women experience it. To find some relief, practice proper posture when sitting and standing, as well as deep breathing. You can also sleep elevated on extra pillows to open the airways.

Pelvic Pain

Pelvic pain intensifies during the third trimester due to the weight of the growing uterus, pubic bone separation, and added pressure from the baby dropping into position for birth. This can lead to round ligament pain, sciatica, and soreness in the lower back, tailbone, and pelvic floor muscles. Deep breathing, yoga, tai chi, Pilates, and other activities that incorporate deep stretching can help alleviate pain.

Major Fetal Developments During the Third Trimester

While you’re nearing the end of pregnancy, your baby (i.e., the fetus) still has a lot of growing to do. During these last weeks, they’ll move more, open their eyes and drop into position to be born. Below, we’re detailing the final stages of pregnancy and fetal development.

Weeks 28-31

During the first few weeks of the third trimester, your baby’s eyes can partially open, and they begin to lose lanugo, the soft, fine, unpigmented hair that covers newborns. By week 31, your baby is the size of a coconut! Additionally:

• They’ll start recognizing voices outside of the womb, mostly yours and your partner/family or whoever you are routinely with
• They can regulate their body temperature within the amniotic fluid
• They can also fully kick, stretch and make grasping motions with their hands

Weeks 32-35

By these weeks, your baby is nearly fully formed, and some have a full head of hair. They now occupy the entire space inside their amniotic sac. By week 35, they are the size of a ripe honeydew melon. Additionally:

• Your baby's brain and nervous system are finishing their development 
• All of their bones are hardening, except for the skull, which will stay soft until 12-18 months
• Their fingernails grow to reach their fingertips

Weeks 36-39

In the final 3-4 weeks of pregnancy, your baby is nearly at their full birth weight and size, and preparing for birth. That means their skin is smoothing out and they’re gaining weight, which will help with body temperature once they're born. By week 39, they’re the size of a full head of romaine lettuce. Additionally,

• Their lungs have matured enough to breathe outside the womb with minimal or no help. However, babies born before 37 weeks are considered premature.
• They have toenails
• The head turns down and then moves into the pelvis as they get closer to week 40

Week 40 and Beyond

Week 40 is your estimated due date, which is calculated as approximately 38 weeks after conception. Your baby may be around 14 inches long and weigh around 7- 8 lbs, though many babies are born smaller or larger. Confirm a healthy birth weight range with your healthcare provider. If your due date comes and goes with no baby, don’t be concerned; most pregnancies last 37 to 42 weeks, and anything beyond 42 weeks is considered post-term, or past due. 

If your baby is past due, your healthcare provider will have an action plan and likely has plenty of prior experience. Continue to monitor how you feel, drink plenty of fluids, rest, and try to stay active. 

Nutrition & Wellness Tips for the Third Trimester

Your body is working overtime in the final stretch of pregnancy, which means third-trimester nutrition, prenatal appointments, and physical activity are more important than ever.

Key Nutrients for the Third Trimester

During this phase of pregnancy, nutrition continues to support your baby’s rapid brain development and bone growth, as well as your energy, sleep, and mood. Here’s how some key nutrients support you and your baby in this stage of pregnancy:

• Iron: Crucial to support blood volume and prevent iron-deficiency anemia. Good sources include spinach, lentils and fortified cereals. Lean meat and poultry are also good sources of iron. 
• Calcium: Vital for building strong bones and teeth, and also supports muscle and nerve function. Good sources include dairy products, leafy greens and fortified plant-based milks. Vitamin D3 also supports strong bones and teeth by helping with calcium absorption. Vitamin K2 also supports bone mineralization by helping regulate calcium use in the body.
• Omega-3s (DHA & EPA): These fatty acids are essential for your baby’s brain and eye development. Good sources include fatty fish, such as salmon and sardines. 
• Choline: A key nutrient for fetal brain and spinal cord development, choline also helps in transporting Omega-3 DHA from mother to baby.
• Vitamin D: Supports immune function, bone health, and heart health. Most of our vitamin D comes from sun exposure, but other sources can include salmon, eggs and fortified cereals. 
• Magnesium: Can help ease muscle cramps, supports sleep, and helps support healthy blood sugar levels. Good sources include nuts, legumes and whole grains.

Good nutritional support remains crucial throughout the final few months of pregnancy. Consider adding Needed’s prenatal multi capsules or powder, Omega-3 or Choline to help you meet your nutrient goals. 

Movement & Exercise

As your baby “drops,” which means they’re getting into position to be born, you may feel increased pressure and pain in your pelvis, lower back, legs and even your ankles and feet. Physical exercise is likely the last thing on your mind, but exercise has many benefits, including a reduced risk of preeclampsia and cesarean birth, among many others. Physical activity can also help strengthen the muscles involved in childbirth; in fact, one study found that women who exercised had shorter labors.

Preparing for Labor & Birth

During these final weeks, recognizing the signs of labor and finalizing your birth plan can help you feel more prepared and confident. 

Signs of Labor to Watch For

Labor often begins gradually, and each experience is unique, but several common signs indicate your body is getting ready for birth:

• Backache: A persistent, dull backache or a heavy, aching feeling in your lower back can be an early sign of labor, especially if accompanied by other symptoms.
• Regular contractions: True labor contractions become progressively longer, stronger, and more frequent. They may feel like intense period cramps or a tightening sensation across the abdomen.
• Losing the Mucus Plug: The loss of the mucus plug (thick, jelly-like mucus your body forms to “plug” the cervical canal during pregnancy) from your cervix can be a sign that labor is starting. It may be clear, pink or brownish-red. It is usually directly preceded by the "bloody show," a small amount of discharge that often contains small traces of mucus.
• Water Breaking: When the amniotic sac surrounding your baby ruptures, it's called the “water breaking.” The fluid is typically clear or pale, and can be a sudden gush or a thin trickle, often signaling that labor is imminent.

Contact your healthcare provider for guidance if you have any of these signs. They can provide tailored advice and tell you when to head to the hospital or birthing center.

Creating Your Birth Plan

Creating a birth plan proactively communicates your labor and delivery preferences with your healthcare team. Here's a birth plan checklist to help get you started:

• Labor Environment: What and who do you want present during labor and delivery? Think of lighting and music preferences as well.
• Pain Management: Indicate whether you will have a natural birth, an epidural, or other pain relief options.
• Labor Positions: Make note of your preferred labor positions, such as squatting or using a birthing ball.
• Delivery Preferences: Consider the scenarios that may occur during labor and list your wishes; examples include an episiotomy or assisted delivery.
• After Birth: Note your preferences for what will happen after the baby is born, such as immediate skin-to-skin contact, delayed cord clamping, or other procedures.
• Feeding Plans: Mention whether you plan to exclusively breastfeed, formula-feed, or a combination of both (consider working with a lactation consultant in advance!)

Remember to thoroughly discuss your birth plan with your healthcare provider to ensure your preferences are understood. However, leave room for flexibility so you’re not stressed over details during labor and delivery.

When to Contact Your Healthcare Provider

Many physical and emotional changes occur during the third trimester, so it can be challenging to figure out what’s considered “normal.” The best rule of thumb is to contact your healthcare provider whenever you feel something is “off.” Don’t hesitate to ask plenty of questions. If you think you’re in active labor and need to go to the hospital, do so immediately. 

Frequently Asked Questions About the Third Trimester

How many weeks is the third trimester?

The third trimester begins at week 28 and lasts until birth, or beyond. That is around 12 weeks or three months.

Does morning sickness come back in the third trimester?

Yes, for some people, nausea or morning sickness can return in the third trimester due to hormonal changes and pressure on the digestive system from the growing uterus.

Why am I having so many braxton-hicks contractions?

Frequent Braxton Hicks contractions are common and normal in the third trimester as your body “practices” for labor.

How to get rid of heartburn while pregnant?

To ease heartburn during pregnancy, try eating smaller meals throughout the day, avoiding spicy or fatty foods, and sleeping with your head elevated. If you experience severe heartburn or other digestive issues, consult your healthcare provider.

What do fetal hiccups feel like in the third trimester?

Fetal hiccups are when the baby has an involuntary contraction of their diaphragm, similar to an adult hiccup. They are normal, do not harm the baby, and tend to ramp up starting at 26 weeks. They can feel like gentle, rhythmic pulses or twitches.

What can I do to prepare for labor?

Preparing for labor looks different for everyone. Generally, you’ll want to attend Lamaze (AKA, childbirth) classes, draft your birth plan, get plenty of rest, and pack your hospital bag. You can also incorporate deep breathing and stretching exercises into your daily wellness routine to help relieve joint and pelvic pain.

Is nausea a sign of labor?

Sometimes, nausea in the third trimester can be a subtle sign that labor is near, especially if other symptoms like cramping or back pain accompany it.

\What should I avoid during the third trimester?

Avoid raw or undercooked foods, heavy lifting, lying flat on your back for long periods, and anything your provider has flagged as unsafe for late pregnancy.

What does losing the mucus plug mean?

Losing your mucus plug (a jelly-like substance your body creates to block the cervix) is a sign your cervix is softening in preparation for labor. However, you may still have several days to several weeks until labor.