Everything y about the Third Trimester of Pregnancy (weeks 28 to 40)

Feeling those powerful kicks and wondering if you’ll ever get a good night’s sleep again?

Welcome to the third trimester of pregnancy, the last and most intense stage of your amazing journey. From week 28 until the big day, you’re on the home stretch. This final countdown is just one part of your larger journey toward pregnancy and postpartum wellness.

Spanning from week 28 right up to your due date (around week 40), this chapter is a whirlwind of intense baby growth and profound maternal changes. You’re balancing sheer excitement with genuine physical challenges, and that’s completely normal.

This isn’t just about counting down the days; it’s about empowering yourself with knowledge. So, take a deep breath. We’ve distilled the latest medical guidance and practical tips into your ultimate guide for these final weeks. Let’s embrace this countdown together. Read on to transform anticipation into readiness and these final weeks of your pregnancy into a period of empowered preparation.

What Is the Third Trimester of Pregnancy & How Long Does It Last?

The third trimester of pregnancy is the final stage of your journey, stretching from week 28 until delivery — typically around week 40, but sometimes up to week 42. This period covers the 7th, 8th, and 9th months of pregnancy, often referred to as the “home stretch” before labor and delivery. If you’re looking to remember your journey, you can always check back at your first trimester and second trimester.

One common question is: “Does the third trimester start at week 27 or 28?” Most major health organizations, including ACOG, recognize week 28 as the official start, though some providers may mark week 27 as the transition point. This slight difference in counting is due to how trimesters are divided by gestational age, but rest assured, you’re entering your third trimester by the time you hit week 28.

From this point on, your uterus continues to grow, your body prepares for childbirth, and your baby undergoes rapid development — gaining weight, maturing vital organs, and settling into position for birth.

It’s often called the “longest” or “hardest” trimester, not because of time (all trimesters are similar in length), but because of the physical intensity. By this stage, many women experience sleep issues, back pain, and fatigue as their body adjusts to the final stretch before labor.

Fetal Development in the Third Trimester: A Week-by-Week Journey

The final three months of pregnancy are a period of astonishing transformation. This stage of fetal development third trimester is less about forming new structures and more about perfecting them, as your baby prepares for life outside the womb.

Your little one is rapidly gaining weight, fine-tuning vital organs, and getting into position for birth. Let’s explore the remarkable baby growth weeks 28–40.

A Month-by-Month Look at Your Baby’s Growth

• Month 7 (Weeks 28-32): The Age of Viability: This is a critically important period. The brain is developing rapidly, creating billions of neural connections. The fetal lungs are now mature enough that, with advanced medical care, a baby born at this time has a strong chance of survival. Your baby begins to store fat under the skin, smoothing out wrinkles and providing essential energy reserves after birth. They also start to open and close their eyes and can perceive light filtering through the amniotic fluid.
• Month 8 (Weeks 33-36): Practice Makes Perfect: Weight gain is the primary goal now, with your baby adding up to half a pound per week. The nervous system and fetal lungs are nearly fully developed. Most babies assume the head-down position this month in preparation for birth. You’ll notice more organized patterns of sleep and wakefulness, and those kicks become stronger, though more like rolls and stretches as space gets tighter. By week 36, you might experience “lightening” or “dropping,” as the baby descends into your pelvis.
• Month 9 (Weeks 37-40): The Final Preparations: Your baby is now considered full-term! The final touches are being added: the lanugo (soft body hair) has mostly shed, and the vernix caseosa (a protective, waxy coating) has thickened. The placenta is working at its peak to deliver antibodies that will provide immune protection after birth. The lungs are fully mature and ready to take their first breath. Most of their energy is now dedicated to gaining those final few ounces before the big day.

Still, this trimester is also filled with excitement — every week brings you closer to meeting your baby, and understanding this timeline helps you prepare both physically and emotionally for birth.

Third Trimester of Pregnancy Symptoms

While the second trimester might have felt like a breeze, the third trimester often brings a whole new set of physical and emotional changes. This stage is often called the “home stretch,” where your baby experiences rapid growth—gaining weight, maturing organs like the lungs and brain, and positioning head-down for delivery.

The uterus expands dramatically, putting pressure on surrounding organs and altering your center of gravity, while hormones like progesterone continue to surge, relaxing joints and ligaments to accommodate the growing fetus. Fetal movement becomes more pronounced, with stronger kicks and rolls that you can feel regularly, serving as a reassuring sign of your baby’s activity.

Third trimester symptoms vary in intensity but are generally normal adaptations to your body’s hard work. Below, we’ll break the Common Third Trimester Symptoms down into categories, with tips for relief based on expert recommendations. Always track fetal movement (aim for at least 10 movements in two hours) and report any concerning changes.

Physical Discomforts & Body Changes

Your body is working overtime, and these third trimester pregnancy symptoms are often a direct result.

• Back Pain & Pelvic Pressure: As your baby gains weight and drops lower into your pelvis (a process called “lightening”), the extra pressure on your back and pelvic floor can cause significant aching and pressure. You might feel a waddling gait is your new normal.
• Fatigue: The sheer physical effort of carrying extra weight, combined with sleep cycles interrupted by discomfort and frequent bathroom trips, can leave you feeling exhausted. This is your body’s way of telling you to rest.
• Swelling (Edema): Mild swelling in your feet, ankles, and hands is common due to increased blood volume and pressure from the uterus on major blood vessels.
• Insomnia: Finding a comfortable sleeping position becomes a nightly puzzle. This, combined with anxiety, hormones, heartburn, and active fetal movement, can make a full night’s sleep elusive.

Digestive System Shifts

Rising hormones and a crowded abdomen continue to impact your digestion.

• Heartburn & Indigestion: The hormone progesterone relaxes the valve between your stomach and esophagus, while your growing baby pushes on your stomach. This double whammy can force stomach acid upward, causing a burning sensation.
• Constipation: That same relaxing effect of progesterone slows down your digestive tract, making bowel movements more difficult and infrequent.

Other Frequent Symptoms

• Shortness of Breath: With your uterus pushing up against your diaphragm, your lungs have less room to expand. You may find yourself winded after even minor exertion.
• Braxton Hicks Contractions: Your body is getting ready for the main event! These “practice contractions” are usually irregular, not overly painful, and taper off with movement or hydration. They are a normal part of the process.
• Frequent Urination: As your baby’s head engages and puts direct pressure on your bladder, you may feel the need to urinate even more often than before.

The Emotional Rollercoaster

The third trimester isn’t just about physical changes. Your emotional world is also in flux.

• Anxiety & Excitement: It’s completely normal to feel a mix of intense excitement to meet your baby and anxiety about labor, delivery, and becoming a parent. This “nesting instinct”—a sudden burst of energy to organize and prepare—is a common manifestation of this.
• Mood Swings: Fluctuating hormones, physical discomfort, and sleep deprivation are a potent mix that can lead to quick shifts in mood. Be gentle with yourself.

Prenatal Care & Tests in the Third Trimester

As you enter the third trimester of pregnancy, prenatal care becomes more frequent and detailed to keep both you and your baby safe. Most providers schedule appointments every two weeks until 36 weeks, and then weekly until delivery. These visits help track your progress as your due date approaches.

During each visit, your provider will typically:

• Check your blood pressure (to screen for preeclampsia).
• Test your urine for protein or glucose.
• Monitor your weight and measure fundal height (uterus growth).
• Listen to the baby’s heartbeat and assess fetal position.

Key Tests in the Third Trimester

• Gestational diabetes screening: Usually between 24–28 weeks, but may be repeated later if needed.
• Anemia screening: Ensures your red blood cell levels are strong enough to support labor and postpartum recovery.
• Group B strep (GBS) test: Done between weeks 35–37 to check for bacteria that could affect the baby during delivery.
• Ultrasounds: Sometimes ordered to check fetal growth, amniotic fluid, or placenta health.

Why these tests matter: They catch complications like gestational diabetes, preeclampsia, or infections early, giving your provider time to plan a safe delivery for you and your baby.