Week 40 of 40 · third trimester

Week 40 of pregnancy

Week 40 is in the last stretch. Much of what's left for the baby is maturing and putting on weight.

Sources checked October 30, 2026

A pregnant woman folding baby clothes on a bed
Week 40
Due date week
About the size of
a watermelon
The Log menu during pregnancy: Symptom, Appointment, Sleep, Mood and Contractions
The Log menu during pregnancy.
Illustration of a watermelon, the average size of a baby at 40 weeks
Your baby this week

About the size of a watermelon

SizeAbout a watermelon
Length20.2 in (51.2 cm), measured from head to heel [1]
Weight8 lb (3,617 g) [3]
TrimesterThird trimester
Weeks to goDue date week

These are averages. Every baby grows at their own pace.

How the baby is getting ready

The baby is squashed but should still move in their usual pattern. If movements slow down or stop, call your midwife or maternity unit straight away. [1]

How your body may feel

Practice contractions shouldn't hurt. Real contractions hurt as your bump goes tight, then ease when the muscles relax. [1]

Everyone's pregnancy is different. If something worries you, call your midwife or doctor.

Worth doing now

Call your hospital or midwife when contractions last at least 60 seconds and come every 5 minutes. [1]

Questions you could bring to your next appointment

  • What should I do if the baby's movements change?
  • Which signs mean it's time to call or come in?
  • Can we go through my birth preferences?

Questions

What if the baby's movements change?

The NHS says to call your midwife or maternity unit straight away if the baby is moving less than usual or the pattern changes. Don't wait until the next day, even in the middle of the night.

Do movements slow down near the end?

They shouldn't. The NHS says you should feel your baby move right up to and during labor. There's no set number of kicks to count: get to know your baby's usual pattern.

Is my baby exactly this size?

Probably not exactly. The length is the average the NHS gives for this week, and the weight is the middle value (50th percentile) of the WHO fetal growth charts. Your scan results are the ones that count.

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