Week by week · Trimester 1

Pregnancy Week 5

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

👶 Your baby this week

The neural tube — future brain and spinal cord — is forming. A tiny heart tube begins to beat by week's end.

💛 How you might feel

Hormones surge: sore breasts, fatigue, frequent urination, and food aversions are all common.

✅ This week's to-do

Calculate your due date with our due date calculator and note your week each Monday.

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.