Week by week · Trimester 1

Pregnancy Week 4

Your baby is about the size of a poppy seed this week.

👶 Your baby this week

The embryo implants and splits into layers that become organs. The placenta begins forming and starts producing hCG.

💛 How you might feel

A missed period — the classic cue to test. Early fatigue and breast tenderness can start now.

✅ This week's to-do

Take a home pregnancy test. If positive, book your first prenatal appointment (usually scheduled for week 8–10).

Please note: General information, not medical advice. Every pregnancy is different — your provider's guidance always wins.

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One short email when you enter a new week — what's developing, what to feel ready for, what to do. Timed to you.