Third trimester · 39 weeks pregnant
Week 39: full term
The ideal window for birth begins.
From 39 weeks and 0 days your baby is full term. The lungs are mature and new skin layers and fat help regulate temperature. Labour could start any day, and movements should stay strong until it does.
Size and weight
About the size of
a mini watermelon
Length
50.7 cm
Weight
3.3 kg
Averages from standard growth charts. Measured crown to rump until week 20 and head to heel afterwards.
How your baby is developing
- The lungs are mature and the brain keeps growing (it will for years).
- New layers of skin and fat help the baby regulate temperature.
- Tear ducts are not fully working yet; newborns cry without tears at first.
- The placenta keeps passing antibodies for protection in the first months.
How you may feel
- Cramps and low back pain
- Contractions
- A "show" or your waters breaking
- Pelvic pressure
- Haemorrhoids
- Swelling
- A mix of excitement and anxiety
Your baby should keep moving right up to and during labour. Fewer movements are never a normal sign that labour is near.
What's next
Tests and appointments
- Weekly visit. A membrane sweep may be offered at 40–41 weeks to encourage labour.
- Your care team will discuss a plan for going past 41 weeks.
What to do this week
- Rest, hydrate and eat; think of it as preparing for a marathon.
- Keep gentle walks going and use upright, forward-leaning positions when comfortable.
- Know where the hospital bag, documents and car keys are.
Call your doctor or maternity hospital if
- Your baby is moving less than usual, or the pattern has changed
- Vaginal bleeding, or your waters break, especially if the fluid is green or brown
- A severe headache, vision changes, pain under the right ribs, or sudden swelling of your face and hands
- Regular painful tightenings before 37 weeks, or severe itching of your palms and soles
If something feels wrong, trust yourself and call 103 or your maternity hospital. You will never be wasting anyone's time.
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