40 weeks pregnant
At 40 weeks you are in month 9 and the third trimester. Your baby is about the size of a watermelon: 51.2 cm and 3.6 kg.
As big as
watermelon
Length
51.2 cm
Weight
3.6 kg
Month
9
Trimester
third trimester
To go
due
Averages. Measured crown to rump up to week 20, crown to heel after that. Healthy babies vary a lot.
Your baby this week
The due date. Though only a small share arrive exactly today.
Your body
It can start any day now; everything may stand ready.
Good to know
The due date is an estimate of a window, not a deadline.
To sort around these weeks
- You are close to or at your due date: rest where you can.
- After 41 weeks your midwife talks you through the next steps.
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Frequently asked questions
How many months is 40 weeks pregnant?
40 weeks pregnant falls in month 9 of your pregnancy.
Which trimester is 40 weeks?
At 40 weeks you are in the third trimester.
How big is a baby at 40 weeks?
On average 51.2 cm, about the size of a watermelon. Healthy babies vary a lot.
How long to go at 40 weeks?
You are due. A birth between 37 and 42 weeks counts as on time.
All weeks
General information, not medical advice. If in doubt, call your midwife or GP. Sources: WHO fetal growth charts (Kiserud et al., PLoS Med 2017); Robinson and Fleming 1975; NHS, Your pregnancy and baby guide.