Week 18 of pregnancy
18 Weeks Pregnant
Second trimester
Baby size
About the size of a bell pepper
14.2 cm
What's developing
You're inside the anatomy scan window (18–22 weeks). Yawning, hiccuping and stretching are all happening.
Common symptoms this week
- Feeling movement
- Leg cramps
- Backache
- Belly button changes
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 18 weeks?
Baby growth chart
Typical fetal length and weight from week 8 to week 40.
Length
cmWeek 18: 14.2 cm
Weight
gramsWeek 18: 190 g
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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