13 weeks pregnant
Hello, second trimester.
In short
At 13 weeks your baby is about the size of a peach, around 6.7 cm long. Hello, second trimester.
- Second trimester, week 13 of about 40.
- If you've chosen shared care, you'll see your GP at least 5 times during pregnancy alongside your maternity unit appointments.
Your baby's ovaries or testes have developed inside the body and the genitals are forming on the outside. It's still too early to see your baby's sex on a scan.
How big is my baby at 13 weeks?
At 13 weeks your baby is about the size of a peach, around 6.7 cm long. 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 13 weeks?
- Your baby's ovaries or testes have developed inside the body and the genitals are forming on the outside.
- It's still too early to see your baby's sex on a scan.
- Bones in the arms and legs are hardening.
- The gut, which had been developing partly outside the body, has now moved inside the tummy.
What changes for me at 13 weeks pregnant?
- Many people find their energy starts to come back in the second trimester.
- A small bump may start to show as your womb grows up and out of your pelvis.
- Hormone changes can cause plaque to build up and make your gums bleed.
What is a good tip for this week?
Brush twice a day, floss once a day and see a dentist at least once during pregnancy. Tell them you're pregnant.
What can a partner do this week?
Take over emptying any cat litter tray, as cat poo can carry an infection that is harmful in pregnancy.
What should I know in Ireland at 13 weeks?
- If you've chosen shared care, you'll see your GP at least 5 times during pregnancy alongside your maternity unit appointments.
When to get help: Contact your midwife, GP or maternity unit if you have any bleeding from your vagina, pain when you pee or a temperature of 38°C or higher. 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.