40 Weeks Pregnant
You’re 40 weeks pregnant — in the third trimester, and this is your due-date week. Your baby is about the size of a small pumpkin this week.
★ Your estimated due date.
How big is your baby at 40 weeks?
Size of a
small pumpkin
Length
~51.2 cm
Weight
~3462 g
Last week your baby was about the size of a mini watermelon; this week it's grown to roughly a small pumpkin.
Sizes are averages from standard fetal-growth references. Every baby grows at its own pace — your provider tracks yours at scans.
Baby development at week 40
This is your due date week — though only about 1 in 20 babies arrive on the exact date. The baby is fully developed and ready to meet you. The skull bones haven't fused, allowing the head to mould slightly during birth. If you go past your due date, your provider will monitor you closely. About the size of a small pumpkin.
Your body at 40 weeks
Common symptoms many people notice around week 40 include:
- Regular contractions when labour begins
- Water breaking (a gush or slow trickle)
- Strong pelvic and back pressure
- Bloody show
Symptoms vary enormously from person to person and pregnancy to pregnancy. Not having a symptom on this list is just as normal as having it.
Tips for week 40
- Most providers discuss options if you pass 41–42 weeks
- Go to your birth setting when contractions meet the timing rule you were given
- Trust your instincts and your care team
What trimester is 40 weeks?
Week 40 falls in the third trimester. As a quick map: the first trimester runs weeks 1–13, the second covers weeks 14–27, and the third is week 28 through birth (a due date is set at 40 weeks). Want your own dates? Our Pregnancy Due Date Calculator shows your due date and exactly how far along you are today.
The third trimester (weeks 28–40+) is about growth and getting ready for birth. Prenatal visits become more frequent, the baby gains most of its weight, and you'll watch for the signs of labour. Tiredness and physical discomfort tend to return as the due date approaches.
Frequently asked questions
- How many months is 40 weeks pregnant?
- 40 weeks pregnant is about 9 months. Pregnancy months don't divide evenly into 4-week blocks, so week-to-month conversions are approximate — most providers track pregnancy by week, not month.
- How big is the baby at 40 weeks?
- At 40 weeks, the baby is about the size of a small pumpkin, roughly 51.2 cm and around 3462 g. These are averages — healthy babies vary, and your provider tracks your baby's own growth curve at scans.
- What trimester is 40 weeks?
- Week 40 is in the third trimester. The first trimester is weeks 1–13, the second is weeks 14–27, and the third is weeks 28 to birth (around week 40).