5 weeks pregnant
Your baby's heart is forming.
In short
At 5 weeks your baby is about the size of a sesame seed. Your baby's heart is forming.
- First trimester, week 5 of about 40.
- If you haven't already, book a GP appointment to confirm your pregnancy and talk about your options for maternity care.
Turn your baby round in 3D every week in the free Lullagram pregnancy section
A hollow tube is forming along your baby's back that will become the brain and spinal cord. The heart is starting out as a simple tube.
How big is my baby at 5 weeks?
At 5 weeks your baby is about the size of a sesame seed. These are typical figures from fetal growth charts. Your own baby may be bigger or smaller, and your scans are what count.
What is my baby doing at 5 weeks?
- A hollow tube is forming along your baby's back that will become the brain and spinal cord.
- The heart is starting out as a simple tube.
- Blood has begun to move through your baby's own tiny blood vessels.
- Some of these vessels will become the umbilical cord that links you to your baby.
What changes for me at 5 weeks pregnant?
- This is usually when a period is missed and many people first wonder if they're pregnant.
- Your baby is making the pregnancy hormone hCG, which is what a home pregnancy test picks up in your pee.
- It's normal to feel a mix of excitement and worry at this stage.
What is a good tip for this week?
Be gentle with yourself. Rest when you can and talk to someone you trust about how you're feeling.
What can a partner do this week?
Let the news settle at your own pace together, as there's no rule about when to tell family and friends.
What should I know in Ireland at 5 weeks?
- If you haven't already, book a GP appointment to confirm your pregnancy and talk about your options for maternity care.
- If you are pregnant and in distress, the HSE My Options service offers free, confidential support by freephone and webchat.
When to get help: Contact your midwife, GP or maternity unit straight away if you have bleeding from your vagina or severe tummy pain. HSE: when to get help.
Want these updates on your phone? The Lullagram app has a free pregnancy section with this week-by-week guide, Irish dates worked out from your due date, a contraction timer and more. When your baby arrives, the baby tracker is ready in the same app.
Guides for your pregnancy: pregnancy care in Ireland · maternity leave and benefit · hospital bag checklist · popular baby names · free IVF in Ireland · due date calculator
Sources and guidance
This page is written to be consistent with the official guidance below. It is general information for parents in Ireland, not medical advice. Links checked 23 September 2026.
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