Trimester 1 · Week 4 of 40
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4 weeks pregnant
Your baby is the size of a poppy seed
Length
0.04″
0.1 cm
Weight
<0.01 oz
Trimester
1
What's happening at 4 weeks
Implantation. The first cells of your baby are nestling into the uterus.
What your baby is doing
A bundle of cells called a blastocyst is dividing rapidly and burrowing into your uterine lining. The amniotic sac is forming.
What's happening to you
Possible spotting, fatigue, breast tenderness. You may have just gotten the faintest line on a test.
On the heartbeat
No heartbeat yet — the cardiac tube hasn't formed. But the cells that will become it are already dividing.
Your journal prompt for week 4
“Write the moment you found out — even if it's still sinking in.”
Write it in CudlyStart your pregnancy story today.
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