Third trimester
Week 40 of Pregnancy
🎃
About the size of a small pumpkin
20.2 in · 51.2 cm · 7.63 lb · 3.46 kg (head to heel)
Your baby this week
- Due date week! The average newborn is about 7.5 pounds and 20 inches long.
- The brain will keep developing for years — a newborn's is only about a quarter of its adult size.
- Newborn reflexes — grasping, rooting, startling — are ready for the outside world.
What you may be feeling
- Braxton Hicks that may become the real thing
- Water breaking (for about 1 in 10, the first sign)
- Final nesting energy
Gentle tips for this week
- Real labor contractions get longer, stronger and closer together — time them, don't guess.
- Going 1-2 weeks past the date is normal; your provider will monitor you both closely.
Common question for week 40
How accurate are due dates, really?
They are a well-calculated midpoint, not a deadline. About 4-5% of babies arrive on the exact day; the large majority arrive between 37 and 42 weeks.
Every pregnancy is different. Sizes are averages, symptoms vary widely, and none of this replaces the guidance of your own provider.