Third trimester
30 weeks pregnant
Your baby is about the size of a cabbage
By Emma Whitfield · Pregnancy & Baby Writer
How big is the baby at 30 weeks pregnant?
At 30 weeks pregnant, your baby is about the size of a cabbage, roughly 39.9cm and around 1300g. The baby's eyesight is developing, though it stays blurry after birth. The soft lanugo hair starts to disappear, and bone marrow takes over red blood cell production. These are typical averages — your midwife's measurements are the ones that matter for your pregnancy.
What might you feel at 30 weeks?
Most people at 30 weeks notice some mix of the symptoms below — and plenty notice none of them. Mood swings can return as hormones and tiredness combine. Braxton Hicks may feel stronger. Your belly button may have popped out — it goes back after birth. None of this is a diagnosis; contact your midwife if something worries you.
Common symptoms this week
- Stronger Braxton Hicks
- Returning mood swings
- Popped-out belly button
- Blurrier concentration ("baby brain")
Symptom lists are typical, never exhaustive — and having none of them is normal too.
What should you do at 30 weeks pregnant?
The useful job this week is practical, not medical. A calming week to prepare mentally — read up on the signs of labour so you know what to look for later. Pair it with the NHS week-by-week guide if you want a second description of the same stage.
Week 30 checklist
- Read up on the signs of labour so late pregnancy feels prepared, not anxious
- Confirm who's on standby for lifts, pets and older children
What else is useful at 30 weeks?
Use the week page for size and symptoms; use the guides below for the decisions that actually sit in this window — pay, packing, car seats, labour signs.
30 weeks pregnant: common questions
What are the signs of labour to look out for?
Regular contractions that get longer, stronger and closer together; a "show" (the mucus plug coming away); your waters breaking; and persistent lower backache. Timing contractions tells you the most. Call your maternity unit when contractions are regular, if waters break, or any time you're unsure.
How big is my baby at 30 weeks pregnant?
At 30 weeks, your baby is approximately the size of a cabbage, about 39.9cm and around 1300g. These are approximate averages — every baby grows at its own pace.
What's happening at 30 weeks pregnant?
The baby's eyesight is developing, though it stays blurry after birth. The soft lanugo hair starts to disappear, and bone marrow takes over red blood cell production. For you: mood swings can return as hormones and tiredness combine. braxton hicks may feel stronger. your belly button may have popped out — it goes back after birth.
Which trimester is 30 weeks?
30 weeks pregnant is in the third trimester. The first trimester runs to the end of week 12, the second from weeks 13 to 26, and the third from week 27 to birth.
Sources & further reading
This is general information, not medical advice — every pregnancy is different. For anything that worries you, and for all your antenatal care, speak to your midwife or GP. If your baby's movements ever slow down or change, contact your maternity unit immediately, day or night. Reviewed August 2026.