31 weeks pregnant
Your baby may be turning head down.
In short
At 31 weeks your baby is about the size of a cantaloupe melon, around 41.8 cm long and 1.71 kg. Your baby may be turning head down.
- Third trimester, week 31 of about 40.
- If you plan to start maternity leave at around 37 or 38 weeks, now is a good time to apply for Maternity Benefit, as you need to apply at least 6 weeks before your leave starts.
Your baby is very active, stretching, sucking fingers and turning. Many babies begin to settle head down around now, but there's plenty of time.
How big is my baby at 31 weeks?
At 31 weeks your baby is about the size of a cantaloupe melon, around 41.8 cm long and 1.71 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 31 weeks?
- Your baby is very active, stretching, sucking fingers and turning.
- Many babies begin to settle head down around now, but there's plenty of time.
- Your baby is getting plumper and less wrinkled by the day.
- Their lungs are developing but aren't ready to work on their own yet.
What changes for me at 31 weeks pregnant?
- Your midwife or doctor may measure your bump and gently feel your tummy to check your baby's position.
- You may notice Braxton Hicks contractions, which are practice tightenings that come and go.
- They are usually irregular, short and not painful.
- Keep noticing your baby's usual pattern and contact your maternity unit straight away if it slows down, changes or stops.
What is a good tip for this week?
If a Braxton Hicks tightening is bothering you, try changing position, taking a short walk or having a warm bath.
What can a partner do this week?
Learn the difference between Braxton Hicks and labour contractions so you both know when to call.
What should I know in Ireland at 31 weeks?
- If you plan to start maternity leave at around 37 or 38 weeks, now is a good time to apply for Maternity Benefit, as you need to apply at least 6 weeks before your leave starts.
When to get help: Before 37 weeks, go to your maternity unit straight away if tightenings get stronger and closer together or you have a gush of fluid, bleeding or a feeling that something isn't right. 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.