Trimester 3
Week 33
Your baby is about the size of a pineapple (full grown).
Length: 43.7 cm · Weight: 1900 g
Common this week: Pelvic pressure, Braxton Hicks, Back pain, Shortness of breath, Fatigue, Stretch marks.
Baby development
- The skull is soft and flexible with gaps (fontanelles) to allow birth.
- The bones are hardening but the skull remains pliable.
- The baby is now drinking about 0.5 litres of amniotic fluid per day.
- Sleep cycles are similar to a newborn — about 20 minutes awake, 40 minutes asleep.
Changes for you
- Pelvic pressure may increase as the baby's head engages.
- You may feel "lightening" — baby dropping lower, which can ease breathing.
- Contractions (Braxton Hicks) are common and can feel more intense.
- Stretch marks may continue to appear on belly, breasts, and thighs.
Tips
- Finalise your birth plan and share it with your midwife or OB.
- Know when to go to the hospital: contractions 5 minutes apart lasting 1 minute for 1 hour (5-1-1 rule).
- Rest as much as possible — you are in the final stretch.
- Consider perineal massage from week 34–35 to help prepare for birth.
Appointments
- Routine antenatal check (now typically every 2 weeks).
Warning signs
- Regular painful contractions before 37 weeks
- Gush of fluid
- Heavy bleeding
- Severe headache
Australian notes
- Most NSW hospitals recommend calling the maternity ward anytime you are unsure. They would rather hear from you than have you wait.
- The Pregnancy, Birth and Baby helpline (1800 882 436) is available 24/7 with midwives on hand for advice.