🤰 Third trimester
33 weeks pregnant
Your baby is about the size of a pineapple
By Emma Whitfield · Pregnancy & Baby Writer
Your baby at 33 weeks
The baby's bones are hardening (except the skull, which stays soft and platey to ease the journey through the birth canal). Their immune system is developing with antibodies from you.
Your body at 33 weeks
You may feel the baby has less room to move — movements change in character but should not reduce in frequency. Report any reduction immediately.
Common symptoms this week
- Changed movement character (rolls and stretches rather than jabs) — frequency should NOT reduce
- Pelvic pressure
- Tiredness
Symptom lists are typical, never exhaustive — and having none of them is normal too.
Focus this week
Pack the hospital bag properly this week if you haven't — labour items, things for you and things for the baby, plus your maternity notes.
Week 33 checklist
- Pack the hospital bag properly: labour items, postnatal items for you, and baby things
- Put your maternity notes (or app login) somewhere your birth partner can grab
33 weeks pregnant: common questions
Do babies move less at the end of pregnancy?
No — this is a dangerous myth. Movements change in character as space tightens (more rolls and stretches, fewer jabs) but should NOT reduce in frequency. Any slowdown or change from your baby's normal pattern needs an immediate call to your maternity unit, at any hour.
How big is my baby at 33 weeks pregnant?
At 33 weeks, your baby is approximately the size of a pineapple, about 43.7cm and around 1900g. These are approximate averages — every baby grows at its own pace.
What's happening at 33 weeks pregnant?
The baby's bones are hardening (except the skull, which stays soft and platey to ease the journey through the birth canal). Their immune system is developing with antibodies from you. For you: you may feel the baby has less room to move — movements change in character but should not reduce in frequency. report any reduction immediately.
Which trimester is 33 weeks?
33 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 July 2026.