Week by week / First trimester
Week 4
Your baby is about the size of a poppy seed. Here is what is happening, what you might feel, and the two or three things worth doing this week.
Size right now
A poppy seed
0.1 cm / 0 in
- Length
- 0.1 cm / 0 in
- Trimester
- First
- To go
- 36 weeks
The baby
Implantation into the uterine wall. The cells split into two groups: one becomes the baby, the other becomes the placenta.
You
Some people get light spotting when implantation happens and mistake it for an early period. A home test may just turn positive at the end of this week.
This week
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Averages, not targets. Babies vary a great deal and a scan that reads differently from this page is not a problem. Anything that worries you is a call to your midwife or doctor, not a search.