At 31 weeks pregnant, you’re well into the third trimester, a phase defined less by brand-new milestones and more by refinement, preparation, and endurance. Your baby is continuing to grow stronger and more coordinated each week, while your body is doing sustained, behind-the-scenes work to support that growth.
This stage of pregnancy can feel both grounding and demanding. Movements are familiar now, your bump is undeniably present, and the rhythm of prenatal care may feel more intentional. You may also notice that your energy, sleep, and emotional landscape are shifting again—all part of your body adjusting to the final stretch.
Here’s what to expect at 31 weeks pregnant, including what’s new with your baby, how you might be feeling, and practical ways to support yourself as you move forward with steadiness and confidence.
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What’s New With Baby
At 31 weeks pregnant, your baby is continuing a period of rapid refinement. While many foundational systems are already in place, this week is about strengthening, smoothing, and preparing—particularly when it comes to the brain, lungs, and nervous system.
Your baby now weighs approximately 3½ to 4 pounds and measures around 16–17 inches head to heel. Weight gain is steady and intentional at this stage, supporting energy stores, muscle tone, and temperature regulation after birth.
One of the most significant developments this week is brain growth. The brain is forming deeper folds and grooves, increasing surface area and supporting more advanced processing. These changes lay the groundwork for learning, memory, and sensory integration—both before birth and long after.
Your baby’s lungs are still maturing, practicing rhythmic breathing movements with amniotic fluid. While full lung maturity comes later, these weeks are critical for strengthening respiratory muscles and preparing for breathing air after delivery.
You may also notice that your baby’s movements feel different. With less room to maneuver, movements often become slower but stronger—more rolling, stretching, and pressing than sharp kicks. This change is expected and reflects your baby’s growth rather than reduced activity.
Hearing continues to sharpen as well. Babies at this stage can recognize familiar voices and may respond to sound or music with movement, offering moments of connection that many parents find grounding.
How You’re Feeling
At 31 weeks, your body is doing sustained, demanding work—and it’s common to feel that effort more clearly now. While experiences vary, many people notice a mix of physical changes and emotional shifts during this stage of the third trimester.
Physical Sensations
Fatigue is common as your body supports ongoing growth while sleep becomes more fragmented. Even if you’re resting, the metabolic demands of pregnancy remain high, which can leave you feeling more tired than earlier weeks.
Sleep disruption may come from a combination of factors: difficulty finding a comfortable position, frequent urination, heartburn, or increased baby movement at night. NHS guidance emphasizes that disrupted sleep is a normal part of late pregnancy, not a personal failure or something you need to “push through.”
You may also notice shortness of breath, especially during activity or when lying flat. This is often due to your uterus pressing upward against your diaphragm. While uncomfortable, it’s usually normal—especially if it eases with rest.
Back, hip, or pelvic discomfort can increase as posture shifts and ligaments continue to soften. Some people find relief with gentle stretching, prenatal yoga, or supportive pillows.
Swelling in the feet or ankles may appear or increase, particularly at the end of the day. Mild swelling is common, but sudden or severe swelling—especially in the face or hands—should always be discussed with your provider.
Emotional and Mental Experiences
Emotionally, week 31 can feel quietly intense. Many parents describe a growing awareness that birth is no longer abstract—it’s approaching. This can bring excitement, tenderness, and moments of vulnerability all at once.
You may also notice moments of forgetfulness or difficulty concentrating, often referred to as “pregnancy brain.” Clinicians recognize this as a common experience influenced by hormonal changes, sleep disruption, and mental load—not a sign that something is wrong.
If feelings of anxiety or low mood feel persistent or overwhelming, reaching out to your healthcare provider is a supportive and appropriate step.
Your To-Do List
Week 31 is a good time to slow the pace slightly and focus on steady support rather than major tasks.
Stay connected to prenatal care.
Third-trimester visits are typically happening every two weeks now. These appointments monitor blood pressure, baby’s growth, and overall wellbeing, and they’re an important space to bring up questions—no matter how small they may feel.
Pay attention to baby’s movement.
Daily movement remains an important indicator of wellbeing. While patterns may shift as space tightens, you should continue to feel consistent activity. If something feels noticeably different, your provider will want to hear from you.
Support sleep where possible.
Side-sleeping, especially on your left side, using pillows to support your belly and back, and allowing yourself daytime rest can make a meaningful difference.
Nourish consistently.
Focus on balanced meals with protein, iron-rich foods, calcium, and healthy fats like DHA. Staying hydrated supports circulation and may help ease swelling.
Begin gentle mental preparation.
You don’t need a finalized birth plan, but it can be helpful to start reflecting on preferences and discussing them with your provider.
This article is for informational purposes only. It is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and we recommend that you always consult with your healthcare provider. To the extent that this article features the advice of physicians or medical practitioners, the views expressed are the views of the cited expert and do not necessarily represent the views of Perelel.
References:
1. Mayo Clinic. 3rd trimester pregnancy: what to expect.
2. What to Expect. 31 Weeks Pregnant.
3. Babylist. 31 Weeks.
4. The Bump. 31 Weeks.
