Week 5 of pregnancy
5 Weeks Pregnant
First trimester
Baby size
About the size of a sesame seed
0.2 cm
What's developing
The neural tube, which becomes the brain and spinal cord, begins to form. The heart is starting to take shape.
Common symptoms this week
- Nausea
- Frequent urination
- Fatigue
- Food aversions
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 5 weeks?
Baby growth chart
Typical fetal length and weight from week 8 to week 40.
Length
cmWeight
gramsTypical 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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