Third Trimester
Week 33: Baby is detecting light and dark through the uterus wall.
Here's everything happening with your baby and your body this week.
Your baby is the size of a
Pineapple
Length
17.2 in
Weight
1.9 kg
Week
33 / 40
💡 Expert tip
Calcium needs are highest now (1,200–1,500 mg/day) — dairy, fortified plant milks, leafy greens, and almonds are good sources.
🌱 Baby's development this week
- Pupils react to light
- Bones continue hardening — calcium needs highest now
- Immune system receiving maternal antibodies rapidly
- Skull remains soft and flexible for birth
Science fact
The fontanelle (soft spot) on a baby
🤰 Your symptoms this week
Lightning crotch
sharp, shooting pelvic pain as baby presses on nerves; startling but harmless
Pelvic girdle pain affects 1 in 5. Physiotherapy helps enormously. Ask your midwife for a referral.
Colostrum leaking from nipples
wear breast pads to prevent embarrassment
Difficulty breathing deeply
temporary; will ease once baby drops
💛 Changes in your body
- Pelvic pressure as baby descends
- Leaking colostrum increasingly common
- Difficulty taking deep breaths
- Insomnia may be significant — use this time to prepare mentally
💙 Mental health this week
Insomnia in late pregnancy has a silver lining: your body is adjusting your sleep architecture to prepare for newborn night waking. This doesn
🥗 Nutrition focus
- Calcium at its most critical — 1200–1500mg/day; your bones donate to baby if you
- ,
- re producing contains more protein and antibodies than mature breast milk — it
- ,
📅 Appointment / test
Discuss birth preferences: episiotomy policy, delayed cord clamping, immediate skin-to-skin, and cord blood options.
✅ This week's checklist
Learn perineal massage technique for week 34 onward
Finalize birth plan and share with your provider
Arrange help for the first 2 weeks postpartum — meals, household tasks, sibling care
Track your pregnancy week by week
Interactive guide · 40 weeks · Fruit size visualizations · Personalized tips
Open Week 33 in Interactive Guide → →