Trimester 3
31 Weeks Pregnant
In week 31, your baby is putting on weight quickly and fine-tuning their lung and brain function. They are becoming more responsive to light and sound from the outside world as they prepare for the big transition to life outside.
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Your baby is the size of a Coconut
41 cm
Length
1.5 kg
Weight
Week 1Week 13 - End of Trimester 1Week 27Week 42
Baby's Development This Week
In week 31, your baby is putting on weight quickly and fine-tuning their lung and brain function. They are becoming more responsive to light and sound from the outside world as they prepare for the big transition to life outside.
- All five senses are functional.
- The fetus processes information and develops memory.
- The brain's neural connections form at an incredible rate.
- Fat continues to accumulate under the skin.
- The fetus is head-down in most cases (but may still flip).
- About 41.1cm — the size of a coconut.
Your Symptoms at Week 31
As you progress through week 31, you may feel more physical strain as your baby grows. Back pain and difficulty finding a comfortable sleeping position are common. Keep your feet up when you can and take pride in how far you've come in this incredible process.
Frequent urination
Lean forward while urinating to fully empty your bladder. (moderate)
Lean forward while urinating to fully empty your bladder. (moderate)
Braxton Hicks
Hydrate and rest. They should be irregular and painless. (moderate)
Hydrate and rest. They should be irregular and painless. (moderate)
Shortness of breath
Maintain good posture; rest between activities. (moderate)
Maintain good posture; rest between activities. (moderate)
Leaking colostrum
Use breast pads for comfort. (mild)
Use breast pads for comfort. (mild)
When to Call Your Doctor
- Contractions that become regular or increasingly painful
- Sudden decrease in baby's movement
- Leaking clear fluid (possible water breaking)
- Severe itching (especially palms and soles — possible cholestasis)
Week 31 Checklist
- ✓Pack your hospital bag (essential)
- ✓Pre-register at your hospital or birth center (recommended)
- ✓Make a list of who to call when labor starts (recommended)
- ✓Discuss pain management options with your provider (recommended)
Frequently Asked Questions
Continue Your Pregnancy Journey — Week 31
← →
Week 30 of Pregnancy
Review what happened last week with your baby's development
← →
Week 32 of Pregnancy
What's coming next week — new developments and symptoms to expect
Guide
Third Trimester Overview
Everything happening during your third trimester — symptoms, tests, and milestones
Symptom
Braxton Hicks Contractions
How to tell practice contractions from the real thing
Symptom
Swollen Feet & Ankles
Normal swelling vs. warning signs of preeclampsia
Tool
Kick Counter
Monitor baby kicks — 10 movements in 2 hours is a healthy baseline
Related
Group B Strep Test
Routine test between weeks 35–37 — what a positive result means
Nutrition
Third Trimester Nutrition
Foods for energy, labor prep, and healthy final weight gain
Medical Disclaimer: This content is for informational purposes only and is not a substitute for professional medical advice. Always consult your healthcare provider for personalized guidance about your pregnancy.