Third Trimester of Pregnancy
The final stretch of your pregnancy journey. Your baby is growing rapidly, and you're preparing for the amazing moment when you finally meet your little one.
Duration
Weeks 27-40+ of pregnancy
Key Focus
Getting ready for labor and delivery
Baby Weight Gain
Baby doubles in weight
👶Your Baby's Development in the Third Trimester
Weeks 27-30: Rapid Brain Development
- • Brain tissue develops rapidly
- • Baby can open and close eyes
- • Sleep patterns become more regular
- • Baby responds to light and sound consistently
- • Bones begin hardening (except skull)
Weeks 31-34: Weight Gain Accelerates
- • Rapid weight gain - about ½ pound per week
- • Baby's movements may feel different due to less space
- • Immune system strengthens
- • Baby practices breathing movements
- • Fingernails reach fingertips
Weeks 35-37: Preparing for Birth
- • Baby is considered early term at 37 weeks
- • Most babies move to head-down position
- • Lungs mature and produce surfactant
- • Baby's grip becomes stronger
- • Fat continues to accumulate for warmth
Weeks 38-40+: Full Term
- • Baby is full term and ready for birth
- • All major organs are fully developed
- • Baby may drop lower into pelvis
- • Movements may decrease due to tight space
- • Baby is ready to survive outside the womb
🤰Your Body Changes in the Third Trimester
Physical Changes
- Growing belly: Significant size increase, may affect mobility
- Weight gain: 25-35 pounds total recommended
- Braxton Hicks: Practice contractions become more noticeable
- Lightning: Baby drops lower in preparation for birth
Common Discomforts
- Shortness of breath: Baby pushes against diaphragm
- Sleep difficulties: Hard to find comfortable position
- Frequent urination: Baby presses on bladder
- Back pain: Extra weight and posture changes
🔬Important Tests & Monitoring
Group B Strep Test (Weeks 35-37)
Screening for bacterial infection that could affect baby during delivery
- • Simple swab test of vagina and rectum
- • If positive, antibiotics during labor prevent transmission
- • About 25% of women carry GBS bacteria harmlessly
Non-Stress Test (If Needed)
Monitors baby's heart rate and movement
- • Usually done if pregnancy goes past due date
- • Monitors baby's well-being
- • Non-invasive test taking 20-40 minutes
Weekly Appointments (Weeks 36-40)
More frequent monitoring as due date approaches
- • Check baby's position and heart rate
- • Monitor signs of labor approaching
- • Check for swelling and blood pressure
- • Discuss birth plan and preferences
🎯Preparing for Labor and Delivery
Signs of Labor
- Regular contractions: Every 5 minutes, lasting 1 minute
- Water breaking: Fluid leak or sudden gush
- Mucus plug: Loss of thick, bloody mucus
- Back pain: Intense, rhythmic lower back pain
Hospital Bag Essentials
- For mom: Comfortable clothes, toiletries, nursing bras
- For baby: Going-home outfit, car seat, blankets
- Documents: ID, insurance cards, birth plan
- Comfort items: Pillows, music, snacks for partner
✓Third Trimester Checklist
Medical Preparations
Home Preparations
Third Trimester Week by Week
Click on any week to get detailed information about your baby's development and your body's changes.
🚨When to Contact Your Healthcare Provider
Call your doctor immediately for these third trimester warning signs:
Labor-Related Signs
- • Regular contractions before 37 weeks
- • Water breaks with green or brown fluid
- • Bright red bleeding
- • Sudden gush of fluid
- • Severe, persistent abdominal pain
Health Warning Signs
- • Decreased baby movement for 24 hours
- • Severe headaches with vision changes
- • Sudden severe swelling
- • High fever over 100.4°F
- • Persistent vomiting
Previous: Second Trimester
Weeks 13-26: The golden period
All Pregnancy Weeks
Complete week-by-week guide
Medical Disclaimer
The information provided about the third trimester of pregnancy is for educational purposes only and should not replace professional medical advice. Always consult with your healthcare provider for personalized medical guidance, especially as you approach your due date.