Week 31 of pregnancy
31 Weeks Pregnant
Third trimester
Baby size
About the size of a coconut
41.1 cm
What's developing
The baby can turn their head from side to side. All five senses are functional.
Common symptoms this week
- Braxton Hicks
- Leaky breasts
- Backache
- Shortness of breath
This is an estimate for information only — only about 1 in 20 babies arrive on their due date. Always confirm dates with your midwife or doctor.
How big is a baby at 31 weeks?
Baby growth chart
Typical fetal length and weight from week 8 to week 40.
Length
cmWeek 31: 41.1 cm
Weight
gramsWeek 31: 1.50 kg
Typical averages based on Hadlock / ACOG references. Weeks 8–20 use crown–rump length; weeks 21–40 switch to crown–heel — that's the small jump you'll see mid-chart. Real babies vary — your ultrasound is the reliable number for you.55
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