33 Weeks Pregnant: What to Expect, Baby Development & Birth Preparation
33 weeks pregnant: what to know right now
Baby: Size of a pineapple (~17.2 inches, ~4.2 lbs) · Bones hardening, lungs nearly mature, skull flexible for birth · Body: Braxton Hicks intensifying, shortness of breath, sleep disrupted · Key milestone: Survival rate 98%+ if born now · Coming up: GBS swab at 35–37 weeks, growth scan if scheduled
Here's everything happening with your baby and your body this week.
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
The fontanelle (soft spot) on a baby
🤰 Your symptoms this week
💛 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
Insomnia in late pregnancy has a silver lining: your body is adjusting your sleep architecture to prepare for newborn night waking. This doesn
Preparing for Birth at 33 Weeks
With approximately 7 weeks to your due date, birth preparation is no longer theoretical. Week 33 is the window to move from planning to doing.
GBS test is coming: Group B streptococcus (GBS) swab happens at 35–37 weeks. Approximately 25% of healthy women carry GBS harmlessly; the test determines whether IV antibiotics are needed during labor to protect the baby. See week 36 for the full GBS guide.
Baby's position matters from now: Most babies are head-down by 33–34 weeks, but some are still breech. Your provider will begin checking position at 34–36 weeks. If baby is breech at 36 weeks, ECV (external cephalic version) is typically offered. There's no action needed at 33 weeks — just awareness.
Practical checklist for week 33:
- Begin or complete antenatal classes if not already done
- Research birth preferences — pain relief, positions, monitoring preferences
- Start packing your hospital bag (finish by week 36)
- Research car seat options and purchase by week 36
- Book maternity photography if desired (33–36 weeks is optimal)
- Read ahead: postpartum recovery — much easier to digest before birth
🥗 Nutrition focus
- Calcium at its most critical — 1200–1500mg/day; your bones donate to baby if you
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- re producing contains more protein and antibodies than mature breast milk — it
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Discuss birth preferences: episiotomy policy, delayed cord clamping, immediate skin-to-skin, and cord blood options.
✅ This week's checklist
Frequently Asked Questions: 33 Weeks Pregnant
How big is baby at 33 weeks?+
At 33 weeks, your baby is approximately 17.2 inches (43.7 cm) long and weighs about 4.2 lbs (1.9 kg) — roughly the size of a pineapple. The skull is still flexible (the sutures won't fuse until after birth), allowing it to compress for delivery.
What are common symptoms at 33 weeks pregnant?+
Common symptoms at 33 weeks: intensifying Braxton Hicks, shortness of breath, heartburn, back and pelvic pain, disrupted sleep, carpal tunnel symptoms (tingling hands), and swelling in feet and ankles by evening. Severe headache with visual changes, sudden significant swelling, or decreased fetal movement warrants same-day assessment.
What trimester is 33 weeks?+
33 weeks is in the third trimester (weeks 28–40). You have approximately 7 weeks until your due date.
What is the GBS test and when is it done?+
The Group B strep (GBS) test is a vaginal and rectal swab done at 35–37 weeks. Approximately 25% of healthy women carry GBS harmlessly. A positive result means IV antibiotics during labor — this reduces the risk of newborn GBS infection by around 90%. See week 36 for the full guide.
Is it safe to give birth at 33 weeks?+
Babies born at 33 weeks have a survival rate of approximately 98% with appropriate NICU care. Primary concerns are lung maturity, temperature regulation, and feeding. Average NICU stay for a 33-weeker is 3–5 weeks, mainly for feeding and growth support. The closer to 39 weeks, the better outcomes for breathing and feeding.
Track your pregnancy week by week
Interactive guide · 40 weeks · Fruit size visualizations · Personalized tips
Explore Week 33 in the Interactive Guide →