🤰 Third trimester
27 weeks pregnant
Your baby is about the size of a cauliflower
By Emma Whitfield · Pregnancy & Baby Writer
Your baby at 27 weeks
Welcome to the third trimester. The baby now sleeps and wakes at regular intervals and may hiccup (you'll feel rhythmic little jolts). Their lungs and brain are developing fast.
Your body at 27 weeks
The final stretch begins. Tiredness can return, along with heartburn, swelling and trouble sleeping. You may notice colostrum (early milk) leaking from your breasts.
Common symptoms this week
- Returning tiredness
- Heartburn
- Baby hiccups (rhythmic jolts)
- Colostrum leaks for some
Symptom lists are typical, never exhaustive — and having none of them is normal too.
Focus this week
From 28 weeks you'll have more frequent antenatal appointments. Keep counting movements and report any change without delay.
Week 27 checklist
- Note the third-trimester appointment schedule — visits get more frequent from 28 weeks
- Keep up movement awareness — pattern changes always warrant a call
27 weeks pregnant: common questions
When does the third trimester start?
At week 27–28 (definitions vary slightly; the NHS uses week 27). It runs to the birth, brings more frequent antenatal appointments, and is when tiredness often returns alongside heartburn and disturbed sleep as the baby takes up more room.
How big is my baby at 27 weeks pregnant?
At 27 weeks, your baby is approximately the size of a cauliflower, about 36.6cm and around 875g. These are approximate averages — every baby grows at its own pace.
What's happening at 27 weeks pregnant?
Welcome to the third trimester. The baby now sleeps and wakes at regular intervals and may hiccup (you'll feel rhythmic little jolts). Their lungs and brain are developing fast. For you: the final stretch begins. tiredness can return, along with heartburn, swelling and trouble sleeping. you may notice colostrum (early milk) leaking from your breasts.
Which trimester is 27 weeks?
27 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.