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Baby size by week

39 weeks pregnant: baby is the size of a mini watermelon

At 39 weeks, baby is about the size of

a mini watermelon

Full term starts this week.

Week 38Week 40

Baby is measured from head to heel at this stage. These are rounded averages. Your ultrasound is the only real measurement of your baby.

Questions moms ask

How big is a baby at 39 weeks?

At 39 weeks, baby is about the size of a mini watermelon: around 50.7 cm (20.0 in) long from head to heel, and weighs about 3.3 kg (7 lb 4 oz). Every baby grows at their own pace.

What trimester is 39 weeks?

39 weeks is in the third trimester.

How many months pregnant is 39 weeks?

Roughly month 9 of 9.

Related tools

This page gives estimates, not medical advice. If you're worried about your baby's growth, talk to your doctor or midwife.