39 weeks pregnant
Ready and waiting.
In short
At 39 weeks your baby is about the size of a small watermelon, around 50.1 cm long and 3.4 kg. Ready and waiting.
- Third trimester, week 39 of about 40.
- From 39 weeks you may be offered a membrane sweep at an appointment, which aims to help labour start. It's your choice whether to have one.
Your baby is ready to be born and is still gaining a little weight. A creamy coating called vernix helps protect their skin and may still be there at birth.
How big is my baby at 39 weeks?
At 39 weeks your baby is about the size of a small watermelon, around 50.1 cm long and 3.4 kg. Before about 14 weeks babies are measured from crown to rump; after that the figure is head to heel. 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 39 weeks?
- Your baby is ready to be born and is still gaining a little weight.
- A creamy coating called vernix helps protect their skin and may still be there at birth.
- Your baby's skin is getting thicker and better at keeping them warm.
- Your baby should keep moving in their usual pattern right up to birth.
What changes for me at 39 weeks pregnant?
- You may have more discharge than usual.
- A show, a sticky plug of mucus that may be yellowish or streaked with blood, can be an early sign that labour is on the way.
- Backache and pressure low in your bump are common as your baby moves down.
What is a good tip for this week?
Keep active if you feel able and rest when you need to, as labour can still be days away after a show.
What can a partner do this week?
Stock the freezer with a few easy meals for the first weeks at home.
What should I know in Ireland at 39 weeks?
- From 39 weeks you may be offered a membrane sweep at an appointment, which aims to help labour start. It's your choice whether to have one.
When to get help: Contact your maternity unit straight away if you have bleeding from your vagina, your waters break or your baby's movements slow down, change or stop. 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.
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.